Moving message bus configurations to its own module

Issue-ID: POLICY-5131
Change-Id: Ibbcdc487300767e7b10d69e9b388c50f09e1adbc
Signed-off-by: adheli.tavares <adheli.tavares@est.tech>

91 files changed, 10464 insertions, 0 deletions

diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/Topic.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/Topic.java
new file mode 100644
index 00000000..48dbb715
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/Topic.java
@@ -0,0 +1,90 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2019 Samsung Electronics Co., Ltd.
+ * Copyright (C) 2022,2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+import java.util.List;
+import org.onap.policy.common.capabilities.Lockable;
+import org.onap.policy.common.capabilities.Startable;
+
+
+/**
+ * Essential Topic Data.
+ */
+public interface Topic extends TopicRegisterable, Startable, Lockable {
+
+    /**
+     * Underlying Communication infrastructure Types.
+     */
+    enum CommInfrastructure {
+        /**
+         * KAFKA Communication Infrastructure.
+         */
+        KAFKA,
+        /**
+         * NOOP for internal use only.
+         */
+        NOOP,
+        /**
+         * REST Communication Infrastructure.
+         */
+        REST
+    }
+
+    /**
+     * Gets the canonical topic name.
+     *
+     * @return topic name
+     */
+    String getTopic();
+
+    /**
+     * Gets the effective topic that is used in
+     * the network communication.  This name is usually
+     * the topic name.
+     *
+     * @return topic name alias
+     */
+    String getEffectiveTopic();
+
+    /**
+     * Gets the communication infrastructure type.
+     *
+     * @return CommInfrastructure object
+     */
+    CommInfrastructure getTopicCommInfrastructure();
+
+    /**
+     * Return list of servers.
+     *
+     * @return bus servers
+     */
+    List<String> getServers();
+
+    /**
+     * Get the more recent events in this topic entity.
+     *
+     * @return array of most recent events
+     */
+    String[] getRecentEvents();
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpoint.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpoint.java
new file mode 100644
index 00000000..5511a82c
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpoint.java
@@ -0,0 +1,238 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2022,2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.common.capabilities.Lockable;
+import org.onap.policy.common.capabilities.Startable;
+import org.onap.policy.common.message.bus.event.kafka.KafkaTopicSink;
+import org.onap.policy.common.message.bus.event.kafka.KafkaTopicSource;
+import org.onap.policy.common.message.bus.event.noop.NoopTopicSink;
+import org.onap.policy.common.message.bus.event.noop.NoopTopicSource;
+import org.onap.policy.common.parameters.topic.TopicParameterGroup;
+import org.onap.policy.common.parameters.topic.TopicParameters;
+
+/**
+ * Abstraction to manage the system's Networked Topic Endpoints, sources of all events input into
+ * the System.
+ */
+public interface TopicEndpoint extends Startable, Lockable {
+
+    /**
+     * Add topics configuration (sources and sinks) into a single list.
+     *
+     * @param properties topic configuration
+     * @return topic list
+     * @throws IllegalArgumentException when invalid arguments are provided
+     */
+    List<Topic> addTopics(Properties properties);
+
+    /**
+     * Add topics configuration (sources and sinks) into a single list.
+     *
+     * @param params parameters to configure topic
+     * @return topic list
+     * @throws IllegalArgumentException when invalid arguments are provided
+     */
+    List<Topic> addTopics(TopicParameterGroup params);
+
+    /**
+     * Add Topic Sources to the communication infrastructure initialized per properties.
+     *
+     * @param properties properties for Topic Source construction
+     * @return a list of generic Topic Sources
+     * @throws IllegalArgumentException when invalid arguments are provided
+     */
+    List<TopicSource> addTopicSources(Properties properties);
+
+
+    /**
+     * Add Topic Sources to the communication infrastructure initialized per properties.
+     *
+     * @param paramList parameters for Topic Source construction
+     * @return a list of generic Topic Sources
+     * @throws IllegalArgumentException when invalid arguments are provided
+     */
+    List<TopicSource> addTopicSources(List<TopicParameters> paramList);
+
+    /**
+     * Add Topic Sinks to the communication infrastructure initialized per properties.
+     *
+     * @param properties properties for Topic Sink construction
+     * @return a list of generic Topic Sinks
+     * @throws IllegalArgumentException when invalid arguments are provided
+     */
+    List<TopicSink> addTopicSinks(Properties properties);
+
+    /**
+     * Add Topic Sinks to the communication infrastructure initialized per properties.
+     *
+     * @param paramList parameters for Topic Sink construction
+     * @return a list of generic Topic Sinks
+     * @throws IllegalArgumentException when invalid arguments are provided
+     */
+    List<TopicSink> addTopicSinks(List<TopicParameters> paramList);
+
+    /**
+     * Gets all Topic Sources.
+     *
+     * @return the Topic Source List
+     */
+    List<TopicSource> getTopicSources();
+
+    /**
+     * Get the Topic Sources for the given topic name.
+     *
+     * @param topicNames the topic name
+     *
+     * @return the Topic Source List
+     * @throws IllegalStateException if the entity is in an invalid state
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    List<TopicSource> getTopicSources(List<String> topicNames);
+
+    /**
+     * Gets the Topic Source for the given topic name and underlying communication infrastructure
+     * type.
+     *
+     * @param commType communication infrastructure type
+     * @param topicName the topic name
+     *
+     * @return the Topic Source
+     * @throws IllegalStateException if the entity is in an invalid state, for example multiple
+     *         TopicReaders for a topic name and communication infrastructure
+     * @throws IllegalArgumentException if invalid parameters are present
+     * @throws UnsupportedOperationException if the operation is not supported.
+     */
+    TopicSource getTopicSource(Topic.CommInfrastructure commType, String topicName);
+
+    /**
+     * Get the Noop Source for the given topic name.
+     *
+     * @param topicName the topic name.
+     * @return the Noop Source.
+     */
+    NoopTopicSource getNoopTopicSource(String topicName);
+
+    /**
+     * Get the Kafka Source for the given topic name.
+     *
+     * @param topicName the topic name.
+     * @return the Kafka Source.
+     */
+    KafkaTopicSource getKafkaTopicSource(String topicName);
+
+    /**
+     * Get the Topic Sinks for the given topic name.
+     *
+     * @param topicNames the topic names
+     * @return the Topic Sink List
+     */
+    List<TopicSink> getTopicSinks(List<String> topicNames);
+
+    /**
+     * Get the Topic Sinks for the given topic name and all the underlying communication
+     * infrastructure type.
+     *
+     * @param topicName the topic name
+     *
+     * @return the Topic Sink List
+     * @throws IllegalStateException if the entity is in an invalid state, for example multiple
+     *         TopicWriters for a topic name and communication infrastructure
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    List<TopicSink> getTopicSinks(String topicName);
+
+    /**
+     * Gets all Topic Sinks.
+     *
+     * @return the Topic Sink List
+     */
+    List<TopicSink> getTopicSinks();
+
+    /**
+     * Get the Topic Sinks for the given topic name and underlying communication infrastructure type.
+     *
+     * @param topicName the topic name
+     * @param commType communication infrastructure type
+     *
+     * @return the Topic Sink List
+     * @throws IllegalStateException if the entity is in an invalid state, for example multiple
+     *         TopicWriters for a topic name and communication infrastructure
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    TopicSink getTopicSink(Topic.CommInfrastructure commType, String topicName);
+
+    /**
+     * Get the no-op Topic Sink for the given topic name.
+     *
+     * @param topicName the topic name
+     *
+     * @return the Topic Source
+     * @throws IllegalStateException if the entity is in an invalid state, for example multiple
+     *         TopicReaders for a topic name and communication infrastructure
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    NoopTopicSink getNoopTopicSink(String topicName);
+
+    /**
+     * Get the KAFKA Topic Source for the given topic name.
+     *
+     * @param topicName the topic name
+     *
+     * @return the Topic Source
+     * @throws IllegalStateException if the entity is in an invalid state, for example multiple
+     *         TopicReaders for a topic name and communication infrastructure
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    KafkaTopicSink getKafkaTopicSink(String topicName);
+
+    /**
+     * Gets only the KAFKA Topic Sources.
+     *
+     * @return the KAFKA Topic Source List
+     */
+    List<KafkaTopicSource> getKafkaTopicSources();
+
+    /**
+     * Gets only the NOOP Topic Sources.
+     *
+     * @return the NOOP Topic Source List
+     */
+    List<NoopTopicSource> getNoopTopicSources();
+
+    /**
+     * Gets only the KAFKA Topic Sinks.
+     *
+     * @return the KAFKA Topic Sinks List
+     */
+    List<KafkaTopicSink> getKafkaTopicSinks();
+
+    /**
+     * Gets only the NOOP Topic Sinks.
+     *
+     * @return the NOOP Topic Sinks List
+     */
+    List<NoopTopicSink> getNoopTopicSinks();
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpointManager.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpointManager.java
new file mode 100644
index 00000000..40b9c235
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpointManager.java
@@ -0,0 +1,36 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class TopicEndpointManager {
+
+    /**
+     * Topic endpoint manager.
+     */
+    @Getter
+    static TopicEndpoint manager = new TopicEndpointProxy();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpointProxy.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpointProxy.java
new file mode 100644
index 00000000..9dbf5418
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicEndpointProxy.java
@@ -0,0 +1,485 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.Properties;
+import lombok.Getter;
+import org.onap.policy.common.capabilities.Startable;
+import org.onap.policy.common.gson.annotation.GsonJsonIgnore;
+import org.onap.policy.common.message.bus.event.kafka.KafkaTopicFactories;
+import org.onap.policy.common.message.bus.event.kafka.KafkaTopicSink;
+import org.onap.policy.common.message.bus.event.kafka.KafkaTopicSource;
+import org.onap.policy.common.message.bus.event.noop.NoopTopicFactories;
+import org.onap.policy.common.message.bus.event.noop.NoopTopicSink;
+import org.onap.policy.common.message.bus.event.noop.NoopTopicSource;
+import org.onap.policy.common.parameters.topic.TopicParameterGroup;
+import org.onap.policy.common.parameters.topic.TopicParameters;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This implementation of the Topic Endpoint Manager, proxies operations to the appropriate
+ * implementation(s).
+ */
+@Getter
+public class TopicEndpointProxy implements TopicEndpoint {
+    /**
+     * Logger.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(TopicEndpointProxy.class);
+
+    /**
+     * Is this element locked boolean.
+     */
+    private volatile boolean locked = false;
+
+    /**
+     * Is this element alive boolean.
+     */
+    private volatile boolean alive = false;
+
+    @Override
+    public List<Topic> addTopics(Properties properties) {
+        List<Topic> topics = new ArrayList<>(addTopicSources(properties));
+        topics.addAll(addTopicSinks(properties));
+        return topics;
+    }
+
+    @Override
+    public List<Topic> addTopics(TopicParameterGroup params) {
+        List<TopicParameters> sinks =
+            (params.getTopicSinks() != null ? params.getTopicSinks() : Collections.emptyList());
+        List<TopicParameters> sources =
+            (params.getTopicSources() != null ? params.getTopicSources() : Collections.emptyList());
+
+        List<Topic> topics = new ArrayList<>(sinks.size() + sources.size());
+        topics.addAll(addTopicSources(sources));
+        topics.addAll(addTopicSinks(sinks));
+        return topics;
+    }
+
+    @Override
+    public List<TopicSource> addTopicSources(List<TopicParameters> paramList) {
+        List<TopicSource> sources = new ArrayList<>(paramList.size());
+
+        for (TopicParameters param : paramList) {
+            switch (Topic.CommInfrastructure.valueOf(param.getTopicCommInfrastructure().toUpperCase())) {
+                case KAFKA:
+                    sources.add(KafkaTopicFactories.getSourceFactory().build(param));
+                    break;
+                case NOOP:
+                    sources.add(NoopTopicFactories.getSourceFactory().build(param));
+                    break;
+                default:
+                    logger.debug("Unknown source type {} for topic: {}", param.getTopicCommInfrastructure(),
+                        param.getTopic());
+                    break;
+            }
+        }
+
+        lockSources(sources);
+
+        return sources;
+    }
+
+    @Override
+    public List<TopicSource> addTopicSources(Properties properties) {
+
+        // 1. Create KAFKA Sources
+        // 2. Create NOOP Sources
+
+        List<TopicSource> sources = new ArrayList<>();
+
+        sources.addAll(KafkaTopicFactories.getSourceFactory().build(properties));
+        sources.addAll(NoopTopicFactories.getSourceFactory().build(properties));
+
+        lockSources(sources);
+
+        return sources;
+    }
+
+    private void lockSources(List<TopicSource> sources) {
+        if (this.isLocked()) {
+            sources.forEach(TopicSource::lock);
+        }
+    }
+
+    @Override
+    public List<TopicSink> addTopicSinks(List<TopicParameters> paramList) {
+        List<TopicSink> sinks = new ArrayList<>(paramList.size());
+
+        for (TopicParameters param : paramList) {
+            switch (Topic.CommInfrastructure.valueOf(param.getTopicCommInfrastructure().toUpperCase())) {
+                case KAFKA:
+                    sinks.add(KafkaTopicFactories.getSinkFactory().build(param));
+                    break;
+                case NOOP:
+                    sinks.add(NoopTopicFactories.getSinkFactory().build(param));
+                    break;
+                default:
+                    logger.debug("Unknown sink type {} for topic: {}", param.getTopicCommInfrastructure(),
+                        param.getTopic());
+                    break;
+            }
+        }
+
+        lockSinks(sinks);
+
+        return sinks;
+    }
+
+    @Override
+    public List<TopicSink> addTopicSinks(Properties properties) {
+        // 1. Create KAFKA Sinks
+        // 2. Create NOOP Sinks
+
+        final List<TopicSink> sinks = new ArrayList<>();
+
+        sinks.addAll(KafkaTopicFactories.getSinkFactory().build(properties));
+        sinks.addAll(NoopTopicFactories.getSinkFactory().build(properties));
+
+        lockSinks(sinks);
+
+        return sinks;
+    }
+
+    private void lockSinks(List<TopicSink> sinks) {
+        if (this.isLocked()) {
+            sinks.forEach(TopicSink::lock);
+        }
+    }
+
+    @Override
+    public List<TopicSource> getTopicSources() {
+
+        final List<TopicSource> sources = new ArrayList<>();
+
+        sources.addAll(KafkaTopicFactories.getSourceFactory().inventory());
+        sources.addAll(NoopTopicFactories.getSourceFactory().inventory());
+
+        return sources;
+    }
+
+    @Override
+    public List<TopicSource> getTopicSources(List<String> topicNames) {
+
+        if (topicNames == null) {
+            throw new IllegalArgumentException("must provide a list of topics");
+        }
+
+        final List<TopicSource> sources = new ArrayList<>();
+
+        topicNames.forEach(topic -> {
+            try {
+                sources.add(Objects.requireNonNull(this.getKafkaTopicSource(topic)));
+            } catch (final Exception e) {
+                logger.debug("No KAFKA source for topic: {}", topic, e);
+            }
+
+            try {
+                sources.add(Objects.requireNonNull(this.getNoopTopicSource(topic)));
+            } catch (final Exception e) {
+                logger.debug("No NOOP source for topic: {}", topic, e);
+            }
+        });
+
+        return sources;
+    }
+
+    @Override
+    public List<TopicSink> getTopicSinks() {
+
+        final List<TopicSink> sinks = new ArrayList<>();
+
+        sinks.addAll(KafkaTopicFactories.getSinkFactory().inventory());
+        sinks.addAll(NoopTopicFactories.getSinkFactory().inventory());
+
+        return sinks;
+    }
+
+    @Override
+    public List<TopicSink> getTopicSinks(List<String> topicNames) {
+
+        if (topicNames == null) {
+            throw new IllegalArgumentException("must provide a list of topics");
+        }
+
+        final List<TopicSink> sinks = new ArrayList<>();
+        for (final String topic : topicNames) {
+            try {
+                sinks.add(Objects.requireNonNull(this.getKafkaTopicSink(topic)));
+            } catch (final Exception e) {
+                logger.debug("No KAFKA sink for topic: {}", topic, e);
+            }
+
+            try {
+                sinks.add(Objects.requireNonNull(this.getNoopTopicSink(topic)));
+            } catch (final Exception e) {
+                logger.debug("No NOOP sink for topic: {}", topic, e);
+            }
+        }
+        return sinks;
+    }
+
+    @Override
+    public List<TopicSink> getTopicSinks(String topicName) {
+        if (topicName == null) {
+            throw paramException(null);
+        }
+
+        final List<TopicSink> sinks = new ArrayList<>();
+
+        try {
+            sinks.add(this.getKafkaTopicSink(topicName));
+        } catch (final Exception e) {
+            logNoSink(topicName, e);
+        }
+
+        try {
+            sinks.add(this.getNoopTopicSink(topicName));
+        } catch (final Exception e) {
+            logNoSink(topicName, e);
+        }
+
+        return sinks;
+    }
+
+    @GsonJsonIgnore
+    @Override
+    public List<KafkaTopicSource> getKafkaTopicSources() {
+        return KafkaTopicFactories.getSourceFactory().inventory();
+    }
+
+    @GsonJsonIgnore
+    @Override
+    public List<NoopTopicSource> getNoopTopicSources() {
+        return NoopTopicFactories.getSourceFactory().inventory();
+    }
+
+    @Override
+    @GsonJsonIgnore
+    public List<KafkaTopicSink> getKafkaTopicSinks() {
+        return KafkaTopicFactories.getSinkFactory().inventory();
+    }
+
+    @GsonJsonIgnore
+    @Override
+    public List<NoopTopicSink> getNoopTopicSinks() {
+        return NoopTopicFactories.getSinkFactory().inventory();
+    }
+
+    @Override
+    public boolean start() {
+
+        synchronized (this) {
+            if (this.locked) {
+                throw new IllegalStateException(this + " is locked");
+            }
+
+            if (this.alive) {
+                return true;
+            }
+
+            this.alive = true;
+        }
+
+        final List<Startable> endpoints = this.getEndpoints();
+
+        var success = true;
+        for (final Startable endpoint : endpoints) {
+            try {
+                success = endpoint.start() && success;
+            } catch (final Exception e) {
+                success = false;
+                logger.error("Problem starting endpoint: {}", endpoint, e);
+            }
+        }
+
+        return success;
+    }
+
+    @Override
+    public boolean stop() {
+
+        /*
+         * stop regardless if it is locked, in other words, stop operation has precedence over
+         * locks.
+         */
+        synchronized (this) {
+            this.alive = false;
+        }
+
+        final List<Startable> endpoints = this.getEndpoints();
+
+        var success = true;
+        for (final Startable endpoint : endpoints) {
+            try {
+                success = endpoint.stop() && success;
+            } catch (final Exception e) {
+                success = false;
+                logger.error("Problem stopping endpoint: {}", endpoint, e);
+            }
+        }
+
+        return success;
+    }
+
+    /**
+     * Gets the endpoints.
+     *
+     * @return list of managed endpoints
+     */
+    @GsonJsonIgnore
+    protected List<Startable> getEndpoints() {
+        final List<Startable> endpoints = new ArrayList<>();
+
+        endpoints.addAll(this.getTopicSources());
+        endpoints.addAll(this.getTopicSinks());
+
+        return endpoints;
+    }
+
+    @Override
+    public void shutdown() {
+        this.stop();
+
+        KafkaTopicFactories.getSourceFactory().destroy();
+        KafkaTopicFactories.getSinkFactory().destroy();
+
+        NoopTopicFactories.getSinkFactory().destroy();
+        NoopTopicFactories.getSourceFactory().destroy();
+
+    }
+
+    @Override
+    public boolean lock() {
+        boolean shouldLock;
+
+        synchronized (this) {
+            shouldLock = !this.locked;
+            this.locked = true;
+        }
+
+        if (shouldLock) {
+            for (final TopicSource source : this.getTopicSources()) {
+                source.lock();
+            }
+
+            for (final TopicSink sink : this.getTopicSinks()) {
+                sink.lock();
+            }
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean unlock() {
+        boolean shouldUnlock;
+
+        synchronized (this) {
+            shouldUnlock = this.locked;
+            this.locked = false;
+        }
+
+        if (shouldUnlock) {
+            for (final TopicSource source : this.getTopicSources()) {
+                source.unlock();
+            }
+
+            for (final TopicSink sink : this.getTopicSinks()) {
+                sink.unlock();
+            }
+        }
+
+        return true;
+    }
+
+    @Override
+    public TopicSource getTopicSource(Topic.CommInfrastructure commType, String topicName) {
+
+        if (commType == null) {
+            throw paramException(topicName);
+        }
+
+        if (topicName == null) {
+            throw paramException(null);
+        }
+
+        return switch (commType) {
+            case KAFKA -> this.getKafkaTopicSource(topicName);
+            case NOOP -> this.getNoopTopicSource(topicName);
+            default -> throw new UnsupportedOperationException("Unsupported " + commType.name());
+        };
+    }
+
+    @Override
+    public TopicSink getTopicSink(Topic.CommInfrastructure commType, String topicName) {
+        if (commType == null) {
+            throw paramException(topicName);
+        }
+
+        if (topicName == null) {
+            throw paramException(null);
+        }
+
+        return switch (commType) {
+            case KAFKA -> this.getKafkaTopicSink(topicName);
+            case NOOP -> this.getNoopTopicSink(topicName);
+            default -> throw new UnsupportedOperationException("Unsupported " + commType.name());
+        };
+    }
+
+    @Override
+    public KafkaTopicSource getKafkaTopicSource(String topicName) {
+        return KafkaTopicFactories.getSourceFactory().get(topicName);
+    }
+
+    @Override
+    public NoopTopicSource getNoopTopicSource(String topicName) {
+        return NoopTopicFactories.getSourceFactory().get(topicName);
+    }
+
+    @Override
+    public KafkaTopicSink getKafkaTopicSink(String topicName) {
+        return KafkaTopicFactories.getSinkFactory().get(topicName);
+    }
+
+    @Override
+    public NoopTopicSink getNoopTopicSink(String topicName) {
+        return NoopTopicFactories.getSinkFactory().get(topicName);
+    }
+
+    private IllegalArgumentException paramException(String topicName) {
+        return new IllegalArgumentException(
+            "Invalid parameter: a communication infrastructure required to fetch " + topicName);
+    }
+
+    private void logNoSink(String topicName, Exception ex) {
+        logger.debug("No sink for topic: {}", topicName, ex);
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicListener.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicListener.java
new file mode 100644
index 00000000..f9896243
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicListener.java
@@ -0,0 +1,37 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+/**
+ * Listener for event messages entering the Policy Engine.
+ */
+@FunctionalInterface
+public interface TopicListener {
+
+    /**
+     * Notification of a new Event over a given Topic.
+     *
+     * @param commType communication infrastructure type
+     * @param topic    topic name
+     * @param event    event message as a string
+     */
+    void onTopicEvent(Topic.CommInfrastructure commType, String topic, String event);
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicRegisterable.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicRegisterable.java
new file mode 100644
index 00000000..1d6873e9
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicRegisterable.java
@@ -0,0 +1,41 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+/**
+ * Marks a Topic entity as registerable.
+ */
+public interface TopicRegisterable {
+
+    /**
+     * Register for notification of events with this Topic Entity.
+     *
+     * @param topicListener the listener of events
+     */
+    void register(TopicListener topicListener);
+
+    /**
+     * Unregisters for notification of events with this Topic Entity.
+     *
+     * @param topicListener the listener of events
+     */
+    void unregister(TopicListener topicListener);
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicSink.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicSink.java
new file mode 100644
index 00000000..d5269b9a
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicSink.java
@@ -0,0 +1,38 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2023-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+/**
+ * Marks a given Topic Endpoint as able to send messages over a topic.
+ */
+public interface TopicSink extends Topic {
+
+    /**
+     * Sends a string message over this Topic Endpoint.
+     *
+     * @param message message to send
+     * @return true if the send operation succeeded, false otherwise
+     * @throws IllegalArgumentException an invalid message has been provided
+     * @throws IllegalStateException    the entity is in a state that prevents
+     *         it from sending messages, for example, locked or stopped.
+     */
+    boolean send(String message);
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicSource.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicSource.java
new file mode 100644
index 00000000..f0dc3b74
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/TopicSource.java
@@ -0,0 +1,36 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+/**
+ * Marker for a Topic Entity, indicating that the entity is able to read
+ * over a topic.
+ */
+public interface TopicSource extends Topic {
+
+    /**
+     * Pushes an event into the source programmatically.
+     *
+     * @param event the event in json format
+     * @return true if it can be processed correctly, false otherwise
+     */
+    boolean offer(String event);
+
+}
\ No newline at end of file
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/ApiKeyEnabled.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/ApiKeyEnabled.java
new file mode 100644
index 00000000..360a88a2
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/ApiKeyEnabled.java
@@ -0,0 +1,39 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+/**
+ * API.
+ */
+public interface ApiKeyEnabled {
+    /**
+     * Get API key.
+     *
+     * @return api key
+     */
+    String getApiKey();
+
+    /**
+     * Get API secret.
+     *
+     * @return api secret
+     */
+    String getApiSecret();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusConsumer.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusConsumer.java
new file mode 100644
index 00000000..925949aa
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusConsumer.java
@@ -0,0 +1,278 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ * Modifications Copyright (C) 2020,2023 Bell Canada. All rights reserved.
+ * Modifications Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.DEFAULT_TIMEOUT_MS_FETCH;
+
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.api.trace.TraceFlags;
+import io.opentelemetry.api.trace.TraceState;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.instrumentation.kafkaclients.v2_6.TracingConsumerInterceptor;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Properties;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import lombok.Data;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.clients.consumer.OffsetAndMetadata;
+import org.apache.kafka.common.TopicPartition;
+import org.apache.kafka.common.header.Headers;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Wrapper around libraries to consume from message bus.
+ */
+public interface BusConsumer {
+
+    /**
+     * fetch messages.
+     *
+     * @return list of messages
+     * @throws IOException when error encountered by underlying libraries
+     */
+    Iterable<String> fetch() throws IOException;
+
+    /**
+     * close underlying library consumer.
+     */
+    void close();
+
+    /**
+     * Consumer that handles fetch() failures by sleeping.
+     */
+    abstract class FetchingBusConsumer implements BusConsumer {
+        private static final Logger logger = LoggerFactory.getLogger(FetchingBusConsumer.class);
+
+        /**
+         * Fetch timeout.
+         */
+        protected int fetchTimeout;
+
+        /**
+         * Time to sleep on a fetch failure.
+         */
+        @Getter
+        private final int sleepTime;
+
+        /**
+         * Counted down when {@link #close()} is invoked.
+         */
+        private final CountDownLatch closeCondition = new CountDownLatch(1);
+
+
+        /**
+         * Constructs the object.
+         *
+         * @param busTopicParams parameters for the bus topic
+         */
+        protected FetchingBusConsumer(BusTopicParams busTopicParams) {
+            this.fetchTimeout = busTopicParams.getFetchTimeout();
+
+            if (this.fetchTimeout <= 0) {
+                this.sleepTime = DEFAULT_TIMEOUT_MS_FETCH;
+            } else {
+                // don't sleep too long, even if fetch timeout is large
+                this.sleepTime = Math.min(this.fetchTimeout, DEFAULT_TIMEOUT_MS_FETCH);
+            }
+        }
+
+        /**
+         * Causes the thread to sleep; invoked after fetch() fails.  If the consumer is closed,
+         * or the thread is interrupted, then this will return immediately.
+         */
+        protected void sleepAfterFetchFailure() {
+            try {
+                logger.info("{}: backoff for {}ms", this, sleepTime);
+                if (this.closeCondition.await(this.sleepTime, TimeUnit.MILLISECONDS)) {
+                    logger.info("{}: closed while handling fetch error", this);
+                }
+
+            } catch (InterruptedException e) {
+                logger.warn("{}: interrupted while handling fetch error", this, e);
+                Thread.currentThread().interrupt();
+            }
+        }
+
+        @Override
+        public void close() {
+            this.closeCondition.countDown();
+        }
+    }
+
+    /**
+     * Kafka based consumer.
+     */
+    class KafkaConsumerWrapper extends FetchingBusConsumer {
+
+        /**
+         * logger.
+         */
+        private static final Logger logger = LoggerFactory.getLogger(KafkaConsumerWrapper.class);
+
+        private static final String KEY_DESERIALIZER = "org.apache.kafka.common.serialization.StringDeserializer";
+
+        /**
+         * Kafka consumer.
+         */
+        protected KafkaConsumer<String, String> consumer;
+        protected Properties kafkaProps;
+
+        protected boolean allowTracing;
+
+        /**
+         * Kafka Consumer Wrapper.
+         * BusTopicParam - object contains the following parameters
+         * servers - messaging bus hosts.
+         * topic - topic
+         *
+         * @param busTopicParams - The parameters for the bus topic
+         */
+        public KafkaConsumerWrapper(BusTopicParams busTopicParams) {
+            super(busTopicParams);
+
+            if (busTopicParams.isTopicInvalid()) {
+                throw new IllegalArgumentException("No topic for Kafka");
+            }
+
+            //Setup Properties for consumer
+            kafkaProps = new Properties();
+            kafkaProps.setProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,
+                busTopicParams.getServers().get(0));
+
+            if (busTopicParams.isAdditionalPropsValid()) {
+                kafkaProps.putAll(busTopicParams.getAdditionalProps());
+            }
+
+            if (kafkaProps.get(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG) == null) {
+                kafkaProps.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, KEY_DESERIALIZER);
+            }
+            if (kafkaProps.get(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG) == null) {
+                kafkaProps.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, KEY_DESERIALIZER);
+            }
+            if (kafkaProps.get(ConsumerConfig.GROUP_ID_CONFIG) == null) {
+                kafkaProps.setProperty(ConsumerConfig.GROUP_ID_CONFIG, busTopicParams.getConsumerGroup());
+            }
+            if (busTopicParams.isAllowTracing()) {
+                this.allowTracing = true;
+                kafkaProps.setProperty(ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG,
+                    TracingConsumerInterceptor.class.getName());
+            }
+
+            consumer = new KafkaConsumer<>(kafkaProps);
+            //Subscribe to the topic
+            consumer.subscribe(List.of(busTopicParams.getTopic()));
+        }
+
+        @Override
+        public Iterable<String> fetch() {
+            ConsumerRecords<String, String> records = this.consumer.poll(Duration.ofMillis(fetchTimeout));
+            if (records == null || records.count() <= 0) {
+                return Collections.emptyList();
+            }
+            List<String> messages = new ArrayList<>(records.count());
+            try {
+                if (allowTracing) {
+                    createParentTraceContext(records);
+                }
+
+                for (TopicPartition partition : records.partitions()) {
+                    List<ConsumerRecord<String, String>> partitionRecords = records.records(partition);
+                    for (ConsumerRecord<String, String> partitionRecord : partitionRecords) {
+                        messages.add(partitionRecord.value());
+                    }
+                    long lastOffset = partitionRecords.get(partitionRecords.size() - 1).offset();
+                    consumer.commitSync(Collections.singletonMap(partition, new OffsetAndMetadata(lastOffset + 1)));
+                }
+            } catch (Exception e) {
+                logger.error("{}: cannot fetch, throwing exception after sleep...", this);
+                sleepAfterFetchFailure();
+                throw e;
+            }
+            return messages;
+        }
+
+        private void createParentTraceContext(ConsumerRecords<String, String> records) {
+            TraceParentInfo traceParentInfo = new TraceParentInfo();
+            for (ConsumerRecord<String, String> consumerRecord : records) {
+
+                Headers consumerRecordHeaders = consumerRecord.headers();
+                traceParentInfo = processTraceParentHeader(consumerRecordHeaders);
+            }
+
+            SpanContext spanContext = SpanContext.createFromRemoteParent(
+                traceParentInfo.getTraceId(), traceParentInfo.getSpanId(),
+                TraceFlags.getSampled(), TraceState.builder().build());
+
+            Context.current().with(Span.wrap(spanContext)).makeCurrent();
+        }
+
+        private TraceParentInfo processTraceParentHeader(Headers headers) {
+            TraceParentInfo traceParentInfo = new TraceParentInfo();
+            if (headers.lastHeader("traceparent") != null) {
+                traceParentInfo.setParentTraceId(new String(headers.lastHeader(
+                    "traceparent").value(), StandardCharsets.UTF_8));
+
+                String[] parts = traceParentInfo.getParentTraceId().split("-");
+                traceParentInfo.setTraceId(parts[1]);
+                traceParentInfo.setSpanId(parts[2]);
+            }
+
+            return traceParentInfo;
+        }
+
+        @Data
+        @NoArgsConstructor
+        private static class TraceParentInfo {
+            private String parentTraceId;
+            private String traceId;
+            private String spanId;
+        }
+
+        @Override
+        public void close() {
+            super.close();
+            this.consumer.close();
+            logger.info("Kafka Consumer exited {}", this);
+        }
+
+        @Override
+        public String toString() {
+            return "KafkaConsumerWrapper [fetchTimeout=" + fetchTimeout + "]";
+        }
+    }
+}
+
+
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusPublisher.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusPublisher.java
new file mode 100644
index 00000000..10c7db2d
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusPublisher.java
@@ -0,0 +1,43 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ * Modifications Copyright (C) 2020,2023 Bell Canada. All rights reserved.
+ * Modifications Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+public interface BusPublisher {
+
+    String NO_MESSAGE_PROVIDED = "No message provided";
+    String LOG_CLOSE = "{}: CLOSE";
+
+    /**
+     * sends a message.
+     *
+     * @param partitionId id
+     * @param message     the message
+     * @return true if success, false otherwise
+     * @throws IllegalArgumentException if no message provided
+     */
+    boolean send(String partitionId, String message);
+
+    /**
+     * closes the publisher.
+     */
+    void close();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicBase.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicBase.java
new file mode 100644
index 00000000..6516945a
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicBase.java
@@ -0,0 +1,109 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2020 Bell Canada. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import lombok.Getter;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+/**
+ * Bus Topic Base.
+ */
+@Getter
+public abstract class BusTopicBase extends TopicBase implements ApiKeyEnabled {
+
+    /**
+     * API Key.
+     */
+    protected String apiKey;
+
+    /**
+     * API Secret.
+     */
+    protected String apiSecret;
+
+    /**
+     * Use https.
+     */
+    protected boolean useHttps;
+
+    /**
+     * Allow tracing.
+     */
+    protected boolean allowTracing;
+
+    /**
+     * allow self-signed certificates.
+     */
+    protected boolean allowSelfSignedCerts;
+
+    /**
+     * Instantiates a new Bus Topic Base.
+     *
+     * <p>servers list of servers
+     * topic: the topic name
+     * apiKey: API Key
+     * apiSecret: API Secret
+     * useHttps: does connection use HTTPS?
+     * allowTracing: Is tracing allowed?
+     * allowSelfSignedCerts: are self-signed certificates allow
+     *
+     * @param busTopicParams holds all our parameters
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    protected BusTopicBase(BusTopicParams busTopicParams) {
+        super(busTopicParams.getServers(), busTopicParams.getTopic(), busTopicParams.getEffectiveTopic());
+        this.apiKey = busTopicParams.getApiKey();
+        this.apiSecret = busTopicParams.getApiSecret();
+        this.useHttps = busTopicParams.isUseHttps();
+        this.allowTracing = busTopicParams.isAllowTracing();
+        this.allowSelfSignedCerts = busTopicParams.isAllowSelfSignedCerts();
+    }
+
+    protected boolean anyNullOrEmpty(String... args) {
+        for (String arg : args) {
+            if (arg == null || arg.isEmpty()) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    protected boolean allNullOrEmpty(String... args) {
+        for (String arg : args) {
+            if (!(arg == null || arg.isEmpty())) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+
+    @Override
+    public String toString() {
+        return "BusTopicBase [apiKey=" + apiKey + ", apiSecret=" + apiSecret + ", useHttps=" + useHttps
+            + ", allowSelfSignedCerts=" + allowSelfSignedCerts + ", toString()=" + super.toString() + "]";
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicSink.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicSink.java
new file mode 100644
index 00000000..54b08619
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicSink.java
@@ -0,0 +1,42 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017, 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2023-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import org.onap.policy.common.message.bus.event.TopicSink;
+
+/**
+ * Topic Sink over Bus Infrastructure (KAFKA).
+ */
+public interface BusTopicSink extends ApiKeyEnabled, TopicSink {
+
+    /**
+     * Sets the partition key for published messages.
+     *
+     * @param partitionKey the partition key
+     */
+    void setPartitionKey(String partitionKey);
+
+    /**
+     * Return the partition key in used by the system to publish messages.
+     *
+     * @return the partition key
+     */
+    String getPartitionKey();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicSource.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicSource.java
new file mode 100644
index 00000000..974c02bb
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/BusTopicSource.java
@@ -0,0 +1,57 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import org.onap.policy.common.message.bus.event.TopicSource;
+
+/**
+ * Generic Topic Source for Bus Communication Infrastructure.
+ *
+ */
+public interface BusTopicSource extends ApiKeyEnabled, TopicSource {
+
+    /**
+     * Gets the consumer group.
+     *
+     * @return consumer group
+     */
+    public String getConsumerGroup();
+
+    /**
+     * Gets the consumer instance.
+     *
+     * @return consumer instance
+     */
+    public String getConsumerInstance();
+
+    /**
+     * Gets the fetch timeout.
+     *
+     * @return fetch timeout
+     */
+    public int getFetchTimeout();
+
+    /**
+     * Gets the fetch limit.
+     *
+     * @return fetch limit
+     */
+    public int getFetchLimit();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/InlineBusTopicSink.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/InlineBusTopicSink.java
new file mode 100644
index 00000000..6a30f00f
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/InlineBusTopicSink.java
@@ -0,0 +1,165 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2018-2019 Samsung Electronics Co., Ltd.
+ * Modifications Copyright (C) 2020 Bell Canada. All rights reserved.
+ * Modifications Copyright (C) 2023-2024 Nordix Foundation.
+* ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import java.util.UUID;
+import lombok.Getter;
+import lombok.Setter;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Transport Agnostic Bus Topic Sink to carry out the core functionality to interact with a sink.
+ *
+ */
+public abstract class InlineBusTopicSink extends BusTopicBase implements BusTopicSink {
+
+    /**
+     * Loggers.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(InlineBusTopicSink.class);
+
+    /**
+     * The partition key to publish to.
+     */
+    @Getter
+    @Setter
+    protected String partitionKey;
+
+    /**
+     * Message bus publisher.
+     */
+    protected BusPublisher publisher;
+
+    /**
+     * Constructor for abstract sink.
+     * @param busTopicParams contains below listed attributes
+     *     servers: servers
+     *     topic: topic
+     *     apiKey: api secret
+     *     apiSecret: api secret
+     *     partitionId: partition id
+     *     useHttps: does connection use HTTPS?
+     *     allowTracing: is tracing allowed?
+     *     allowSelfSignedCerts: are self-signed certificates allow     *
+     * @throws IllegalArgumentException if invalid parameters are passed in
+     */
+    protected InlineBusTopicSink(BusTopicParams busTopicParams) {
+
+        super(busTopicParams);
+
+        if (busTopicParams.isPartitionIdInvalid()) {
+            this.partitionKey = UUID.randomUUID().toString();
+        } else {
+            this.partitionKey = busTopicParams.getPartitionId();
+        }
+    }
+
+    /**
+     * Initialize the Bus publisher.
+     */
+    public abstract void init();
+
+    @Override
+    public boolean start() {
+        logger.info("{}: starting", this);
+
+        synchronized (this) {
+            if (!this.alive) {
+                if (locked) {
+                    throw new IllegalStateException(this + " is locked.");
+                }
+
+                this.init();
+                this.alive = true;
+            }
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean stop() {
+
+        BusPublisher publisherCopy;
+        synchronized (this) {
+            this.alive = false;
+            publisherCopy = this.publisher;
+            this.publisher = null;
+        }
+
+        if (publisherCopy != null) {
+            try {
+                publisherCopy.close();
+            } catch (Exception e) {
+                logger.warn("{}: cannot stop publisher because of {}", this, e.getMessage(), e);
+            }
+        } else {
+            logger.warn("{}: there is no publisher", this);
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean send(String message) {
+
+        if (message == null || message.isEmpty()) {
+            throw new IllegalArgumentException("Message to send is empty");
+        }
+
+        if (!this.alive) {
+            throw new IllegalStateException(this + " is stopped");
+        }
+
+        try {
+            synchronized (this) {
+                this.recentEvents.add(message);
+            }
+
+            NetLoggerUtil.log(EventType.OUT, this.getTopicCommInfrastructure(), this.topic, message);
+
+            publisher.send(this.partitionKey, message);
+            broadcast(message);
+        } catch (Exception e) {
+            logger.warn("{}: cannot send because of {}", this, e.getMessage(), e);
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void shutdown() {
+        this.stop();
+    }
+
+    @Override
+    public String toString() {
+        return "InlineBusTopicSink [partitionId=" + partitionKey + ", alive=" + alive + ", publisher=" + publisher
+                        + "]";
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSource.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSource.java
new file mode 100644
index 00000000..912b698c
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSource.java
@@ -0,0 +1,288 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2017-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2018-2019 Samsung Electronics Co., Ltd.
+ * Modifications Copyright (C) 2020 Bell Canada. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.NO_LIMIT_FETCH;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.NO_TIMEOUT_MS_FETCH;
+
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.util.UUID;
+import lombok.Getter;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.utils.network.NetworkUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This topic source implementation specializes in reading messages over a bus topic source and
+ * notifying its listeners.
+ */
+public abstract class SingleThreadedBusTopicSource extends BusTopicBase
+        implements Runnable, BusTopicSource {
+
+    /**
+     * Not to be converted to PolicyLogger. This will contain all in/out traffic and only
+     * that in a single file in a concise format.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(SingleThreadedBusTopicSource.class);
+
+    /**
+     * Bus consumer group.
+     */
+    @Getter
+    protected final String consumerGroup;
+
+    /**
+     * Bus consumer instance.
+     */
+    @Getter
+    protected final String consumerInstance;
+
+    /**
+     * Bus fetch timeout.
+     */
+    @Getter
+    protected final int fetchTimeout;
+
+    /**
+     * Bus fetch limit.
+     */
+    @Getter
+    protected final int fetchLimit;
+
+    /**
+     * Message Bus Consumer.
+     */
+    protected BusConsumer consumer;
+
+    /**
+     * Independent thread reading message over my topic.
+     */
+    protected Thread busPollerThread;
+
+
+    /**
+     * Constructor.
+     *
+     * @param busTopicParams topic parameters
+     *
+     * @throws IllegalArgumentException An invalid parameter passed in
+     */
+    protected SingleThreadedBusTopicSource(BusTopicParams busTopicParams) {
+
+        super(busTopicParams);
+
+        if (busTopicParams.isConsumerGroupInvalid() && busTopicParams.isConsumerInstanceInvalid()) {
+            this.consumerGroup = UUID.randomUUID().toString();
+            this.consumerInstance = NetworkUtil.getHostname();
+
+        } else if (busTopicParams.isConsumerGroupInvalid()) {
+            this.consumerGroup = UUID.randomUUID().toString();
+            this.consumerInstance = busTopicParams.getConsumerInstance();
+
+        } else if (busTopicParams.isConsumerInstanceInvalid()) {
+            this.consumerGroup = busTopicParams.getConsumerGroup();
+            this.consumerInstance = UUID.randomUUID().toString();
+
+        } else {
+            this.consumerGroup = busTopicParams.getConsumerGroup();
+            this.consumerInstance = busTopicParams.getConsumerInstance();
+        }
+
+        if (busTopicParams.getFetchTimeout() <= 0) {
+            this.fetchTimeout = NO_TIMEOUT_MS_FETCH;
+        } else {
+            this.fetchTimeout = busTopicParams.getFetchTimeout();
+        }
+
+        if (busTopicParams.getFetchLimit() <= 0) {
+            this.fetchLimit = NO_LIMIT_FETCH;
+        } else {
+            this.fetchLimit = busTopicParams.getFetchLimit();
+        }
+
+    }
+
+    /**
+     * Initialize the Bus client.
+     */
+    public abstract void init() throws MalformedURLException;
+
+    @Override
+    public void register(TopicListener topicListener) {
+
+        super.register(topicListener);
+
+        try {
+            if (!alive && !locked) {
+                this.start();
+            } else {
+                logger.info("{}: register: start not attempted", this);
+            }
+        } catch (Exception e) {
+            logger.warn("{}: cannot start after registration of because of: {}", this, topicListener, e);
+        }
+    }
+
+    @Override
+    public void unregister(TopicListener topicListener) {
+        boolean stop;
+        synchronized (this) {
+            super.unregister(topicListener);
+            stop = this.topicListeners.isEmpty();
+        }
+
+        if (stop) {
+            this.stop();
+        }
+    }
+
+    @Override
+    public boolean start() {
+        logger.info("{}: starting", this);
+
+        synchronized (this) {
+
+            if (alive) {
+                return true;
+            }
+
+            if (locked) {
+                throw new IllegalStateException(this + " is locked.");
+            }
+
+            if (this.busPollerThread == null || !this.busPollerThread.isAlive() || this.consumer == null) {
+
+                try {
+                    this.init();
+                    this.alive = true;
+                    this.busPollerThread = makePollerThread();
+                    this.busPollerThread.setName(this.getTopicCommInfrastructure() + "-source-" + this.getTopic());
+                    busPollerThread.start();
+                    return true;
+                } catch (Exception e) {
+                    throw new IllegalStateException(this + ": cannot start", e);
+                }
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Makes a new thread to be used for polling.
+     *
+     * @return a new Thread
+     */
+    protected Thread makePollerThread() {
+        return new Thread(this);
+    }
+
+    @Override
+    public boolean stop() {
+        logger.info("{}: stopping", this);
+
+        synchronized (this) {
+            BusConsumer consumerCopy = this.consumer;
+
+            this.alive = false;
+            this.consumer = null;
+
+            if (consumerCopy != null) {
+                try {
+                    consumerCopy.close();
+                } catch (Exception e) {
+                    logger.warn("{}: stop failed because of {}", this, e.getMessage(), e);
+                }
+            }
+        }
+
+        Thread.yield();
+
+        return true;
+    }
+
+    /**
+     * Run thread method for the Bus Reader.
+     */
+    @Override
+    public void run() {
+        while (this.alive) {
+            try {
+                fetchAllMessages();
+            } catch (IOException | RuntimeException e) {
+                logger.error("{}: cannot fetch", this, e);
+            }
+        }
+
+        logger.info("{}: exiting thread", this);
+    }
+
+    private void fetchAllMessages() throws IOException {
+        for (String event : this.consumer.fetch()) {
+            synchronized (this) {
+                this.recentEvents.add(event);
+            }
+
+            NetLoggerUtil.log(EventType.IN, this.getTopicCommInfrastructure(), this.topic, event);
+
+            broadcast(event);
+
+            if (!this.alive) {
+                return;
+            }
+        }
+    }
+
+    @Override
+    public boolean offer(String event) {
+        if (!this.alive) {
+            throw new IllegalStateException(this + " is not alive.");
+        }
+
+        synchronized (this) {
+            this.recentEvents.add(event);
+        }
+
+        NetLoggerUtil.log(EventType.IN, this.getTopicCommInfrastructure(), this.topic, event);
+
+        return broadcast(event);
+    }
+
+    @Override
+    public String toString() {
+        return "SingleThreadedBusTopicSource [consumerGroup=" + consumerGroup + ", consumerInstance=" + consumerInstance
+                + ", fetchTimeout=" + fetchTimeout + ", fetchLimit=" + fetchLimit + ", consumer=" + this.consumer
+                + ", alive=" + alive + ", locked=" + locked + ", uebThread=" + busPollerThread + ", topicListeners="
+                + topicListeners.size() + ", toString()=" + super.toString() + "]";
+    }
+
+    @Override
+    public void shutdown() {
+        this.stop();
+        this.topicListeners.clear();
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBase.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBase.java
new file mode 100644
index 00000000..4d1fbc9e
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBase.java
@@ -0,0 +1,243 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2020 Bell Canada. All rights reserved.
+ * Modifications Copyright (C) 2023-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import java.util.ArrayList;
+import java.util.List;
+import lombok.AccessLevel;
+import lombok.Getter;
+import org.apache.commons.collections4.queue.CircularFifoQueue;
+import org.onap.policy.common.message.bus.event.Topic;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Getter
+public abstract class TopicBase implements Topic {
+
+    /**
+     * Logger.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(TopicBase.class);
+
+    /**
+     * List of servers.
+     */
+    protected List<String> servers;
+
+    /**
+     * Topic.
+     */
+    protected final String topic;
+
+    /**
+     * Topic Alias.
+     */
+    protected final String effectiveTopic;
+
+    /**
+     * Event cache.
+     */
+    protected CircularFifoQueue<String> recentEvents = new CircularFifoQueue<>(10);
+
+    /**
+     * Am I running? reflects invocation of start()/stop() !locked & start() => alive stop() =>
+     * !alive.
+     */
+    protected volatile boolean alive = false;
+
+    /**
+     * Am I locked? reflects invocation of lock()/unlock() operations locked => !alive (but not in
+     * the other direction necessarily) locked => !offer, !run, !start, !stop (but this last one is
+     * obvious since locked => !alive).
+     */
+    protected volatile boolean locked = false;
+
+    /**
+     * All my subscribers for new message notifications.
+     */
+    @Getter(AccessLevel.NONE)
+    protected final ArrayList<TopicListener> topicListeners = new ArrayList<>();
+
+    /**
+     * Instantiates a new Topic Base.
+     *
+     * @param servers list of servers
+     * @param topic topic name
+     *
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    protected TopicBase(List<String> servers, String topic) {
+        this(servers, topic, topic);
+    }
+
+    /**
+     * Instantiates a new Topic Base.
+     *
+     * @param servers list of servers
+     * @param topic topic name
+     *
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    protected TopicBase(List<String> servers, String topic, String effectiveTopic) {
+
+        if (servers == null || servers.isEmpty()) {
+            throw new IllegalArgumentException("Server(s) must be provided");
+        }
+
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException("A Topic must be provided");
+        }
+
+        String effectiveTopicCopy;
+        if (effectiveTopic == null || effectiveTopic.isEmpty()) {
+            effectiveTopicCopy = topic;
+        } else {
+            effectiveTopicCopy = effectiveTopic;
+        }
+
+        this.servers = servers;
+        this.topic = topic.toLowerCase();
+        this.effectiveTopic = effectiveTopicCopy.toLowerCase();
+    }
+
+    @Override
+    public void register(TopicListener topicListener) {
+
+        logger.info("{}: registering {}", this, topicListener);
+
+        synchronized (this) {
+            if (topicListener == null) {
+                throw new IllegalArgumentException("TopicListener must be provided");
+            }
+
+            for (TopicListener listener : this.topicListeners) {
+                if (listener == topicListener) {
+                    return;
+                }
+            }
+
+            this.topicListeners.add(topicListener);
+        }
+    }
+
+    @Override
+    public void unregister(TopicListener topicListener) {
+
+        logger.info("{}: unregistering {}", this, topicListener);
+
+        synchronized (this) {
+            if (topicListener == null) {
+                throw new IllegalArgumentException("TopicListener must be provided");
+            }
+
+            this.topicListeners.remove(topicListener);
+        }
+    }
+
+    /**
+     * Broadcast event to all listeners.
+     *
+     * @param message the event
+     * @return true if all notifications are performed with no error, false otherwise
+     */
+    protected boolean broadcast(String message) {
+        List<TopicListener> snapshotListeners = this.snapshotTopicListeners();
+
+        var success = true;
+        for (TopicListener topicListener : snapshotListeners) {
+            try {
+                topicListener.onTopicEvent(this.getTopicCommInfrastructure(), this.topic, message);
+            } catch (Exception e) {
+                logger.warn("{}: notification error @ {} because of {}", this, topicListener, e.getMessage(), e);
+                success = false;
+            }
+        }
+        return success;
+    }
+
+    /**
+     * Take a snapshot of current topic listeners.
+     *
+     * @return the topic listeners
+     */
+    protected synchronized List<TopicListener> snapshotTopicListeners() {
+        @SuppressWarnings("unchecked")
+        List<TopicListener> listeners = (List<TopicListener>) topicListeners.clone();
+        return listeners;
+    }
+
+    @Override
+    public boolean lock() {
+
+        logger.info("{}: locking", this);
+
+        synchronized (this) {
+            if (this.locked) {
+                return true;
+            }
+
+            this.locked = true;
+        }
+
+        return this.stop();
+    }
+
+    @Override
+    public boolean unlock() {
+        logger.info("{}: unlocking", this);
+
+        synchronized (this) {
+            if (!this.locked) {
+                return true;
+            }
+
+            this.locked = false;
+        }
+
+        try {
+            return this.start();
+        } catch (Exception e) {
+            logger.warn("{}: cannot after unlocking because of {}", this, e.getMessage(), e);
+            return false;
+        }
+    }
+
+    @Override
+    public synchronized String[] getRecentEvents() {
+        var events = new String[recentEvents.size()];
+        return recentEvents.toArray(events);
+    }
+
+
+    @Override
+    public String toString() {
+        return "TopicBase [servers=" + servers
+            + ", topic=" + topic
+            + ", effectiveTopic=" + effectiveTopic
+            + ", #recentEvents=" + recentEvents.size()
+            + ", locked=" + locked
+            + ", #topicListeners=" + topicListeners.size()
+            + "]";
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBaseFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBaseFactory.java
new file mode 100644
index 00000000..d98de653
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBaseFactory.java
@@ -0,0 +1,87 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.common.message.bus.event.Topic;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+/**
+ * Topic Base Factory.
+ *
+ * @param <T> Type.
+ */
+public interface TopicBaseFactory<T extends Topic> {
+
+    /**
+     * build a TopicBase instance.
+     *
+     * @param properties properties.
+     * @return T instance.
+     */
+    List<T> build(Properties properties);
+
+    /**
+     * build a TopicBase instance.
+     *
+     * @param servers servers.
+     * @param topic topic.
+     * @param managed managed.
+     * @return T instance.
+     */
+    T build(List<String> servers, String topic, boolean managed);
+
+    /**
+     * Construct an instance of an endpoint.
+     *
+     * @param param parameters
+     * @return an instance of T.
+     */
+    T build(BusTopicParams param);
+
+    /**
+     * destroy TopicBase instance.
+     * @param topic topic.
+     */
+    void destroy(String topic);
+
+    /**
+     * destroy.
+     */
+    void destroy();
+
+    /**
+     * get T instance.
+     *
+     * @param topic topic.
+     * @return T instance.
+     */
+    T get(String topic);
+
+    /**
+     * inventory of T instances.
+     *
+     * @return T instance list.
+     */
+    List<T> inventory();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBaseHashedFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBaseHashedFactory.java
new file mode 100644
index 00000000..70ff04e4
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/base/TopicBaseHashedFactory.java
@@ -0,0 +1,207 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.common.message.bus.event.Topic;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+/**
+ * Topic Factory implementation that indexes T instances in a hash table.
+ */
+public abstract class TopicBaseHashedFactory<T extends Topic> implements TopicBaseFactory<T> {
+
+    protected static final String MISSING_TOPIC_MESSAGE = "A topic must be provided";
+    protected static final String MISSING_SERVERS_MESSAGE = "Servers must be provided";
+
+    /**
+     * endpoints.
+     */
+    protected final HashMap<String, T> endpoints = new HashMap<>();
+
+    /**
+     * get the topic names.
+     *
+     * @param properties properties.
+     * @return list of topic names.
+     */
+    protected abstract List<String> getTopicNames(Properties properties);
+
+    /**
+     * get the servers that this topic uses.
+     *
+     * @param topicName name.
+     * @param properties properties.
+     * @return list of servers.
+     */
+    protected abstract List<String> getServers(String topicName, Properties properties);
+
+    /**
+     * Determines if this topic is managed.
+     *
+     * @param topicName name.
+     * @param properties properties.
+     * @return if managed.
+     */
+    protected abstract boolean isManaged(String topicName, Properties properties);
+
+    /**
+     * construct an instance of an endpoint.
+     *
+     * @param servers servers,
+     * @param topic topic.
+     * @return an instance of T.
+     */
+    public abstract T build(List<String> servers, String topic);
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public List<T> build(Properties properties) {
+        List<String> topicNames = getTopicNames(properties);
+        if (topicNames == null || topicNames.isEmpty()) {
+            return Collections.emptyList();
+        }
+
+        List<T> newEndpoints = new ArrayList<>();
+        synchronized (this) {
+            for (String name : topicNames) {
+                if (this.endpoints.containsKey(name)) {
+                    newEndpoints.add(this.endpoints.get(name));
+                    continue;
+                }
+
+                newEndpoints.add(this.build(getServers(name, properties), name, isManaged(name, properties)));
+            }
+        }
+        return newEndpoints;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public T build(BusTopicParams param) {
+        return this.build(param.getServers(), param.getTopic(), param.isManaged());
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public T build(List<String> servers, String topic, boolean managed) {
+        if (servers == null || servers.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_SERVERS_MESSAGE);
+        }
+
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC_MESSAGE);
+        }
+
+        synchronized (this) {
+            if (this.endpoints.containsKey(topic)) {
+                return this.endpoints.get(topic);
+            }
+
+            var endpoint = build(servers, topic);
+            if (managed) {
+                this.endpoints.put(topic, endpoint);
+            }
+
+            return endpoint;
+        }
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void destroy(String topic) {
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC_MESSAGE);
+        }
+
+        T endpoint;
+        synchronized (this) {
+            if (!this.endpoints.containsKey(topic)) {
+                return;
+            }
+
+            endpoint = this.endpoints.remove(topic);
+        }
+        endpoint.shutdown();
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void destroy() {
+        final List<T> snapshotEndpoints = this.inventory();
+        for (final T snapshot : snapshotEndpoints) {
+            snapshot.shutdown();
+        }
+
+        synchronized (this) {
+            this.endpoints.clear();
+        }
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public T get(String topic) {
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC_MESSAGE);
+        }
+
+        synchronized (this) {
+            if (this.endpoints.containsKey(topic)) {
+                return this.endpoints.get(topic);
+            } else {
+                throw new IllegalStateException(topic + " not found");
+            }
+        }
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public List<T> inventory() {
+        return new ArrayList<>(this.endpoints.values());
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "TopicBaseHashedFactory[ " + super.toString() + " ]";
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClient.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClient.java
new file mode 100644
index 00000000..6ffc188d
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClient.java
@@ -0,0 +1,222 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2020-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2023-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.client;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.BlockingDeque;
+import java.util.concurrent.LinkedBlockingDeque;
+import java.util.concurrent.TimeUnit;
+import lombok.Getter;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.TopicEndpoint;
+import org.onap.policy.common.message.bus.event.TopicEndpointManager;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.onap.policy.common.message.bus.event.TopicSink;
+import org.onap.policy.common.message.bus.event.TopicSource;
+import org.onap.policy.common.utils.coder.Coder;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A "bidirectional" topic, which is a pair of topics, one of which is used to publish
+ * requests and the other to receive responses.
+ */
+@Getter
+public class BidirectionalTopicClient {
+    private static final Logger logger = LoggerFactory.getLogger(BidirectionalTopicClient.class);
+    private static final Coder coder = new StandardCoder();
+
+    private final String sinkTopic;
+    private final String sourceTopic;
+    private final TopicSink sink;
+    private final TopicSource source;
+    private final CommInfrastructure sinkTopicCommInfrastructure;
+    private final CommInfrastructure sourceTopicCommInfrastructure;
+
+    /**
+     * Used when checking whether a message sent on the sink topic can be received
+     * on the source topic. When a matching message is received on the incoming topic,
+     * {@code true} is placed on the queue. If {@link #stopWaiting()} is called or the waiting
+     * thread is interrupted, then {@code false} is placed on the queue. Whenever a value
+     * is pulled from the queue, it is immediately placed back on the queue.
+     */
+    private final BlockingDeque<Boolean> checkerQueue = new LinkedBlockingDeque<>();
+
+
+    /**
+     * Constructs the object.
+     *
+     * @param sinkTopic sink topic name
+     * @param sourceTopic source topic name
+     * @throws BidirectionalTopicClientException if either topic does not exist
+     */
+    public BidirectionalTopicClient(String sinkTopic, String sourceTopic) throws BidirectionalTopicClientException {
+        this.sinkTopic = sinkTopic.toLowerCase();
+        this.sourceTopic = sourceTopic.toLowerCase();
+
+        // init sinkClient
+        List<TopicSink> sinks = getTopicEndpointManager().getTopicSinks(sinkTopic);
+        if (sinks.isEmpty()) {
+            throw new BidirectionalTopicClientException("no sinks for topic: " + sinkTopic);
+        } else if (sinks.size() > 1) {
+            throw new BidirectionalTopicClientException("too many sinks for topic: " + sinkTopic);
+        }
+
+        this.sink = sinks.get(0);
+
+        // init source
+        List<TopicSource> sources = getTopicEndpointManager().getTopicSources(Collections.singletonList(sourceTopic));
+        if (sources.isEmpty()) {
+            throw new BidirectionalTopicClientException("no sources for topic: " + sourceTopic);
+        } else if (sources.size() > 1) {
+            throw new BidirectionalTopicClientException("too many sources for topic: " + sourceTopic);
+        }
+
+        this.source = sources.get(0);
+
+        this.sinkTopicCommInfrastructure = sink.getTopicCommInfrastructure();
+        this.sourceTopicCommInfrastructure = source.getTopicCommInfrastructure();
+    }
+
+    public boolean send(String message) {
+        return sink.send(message);
+    }
+
+    public void register(TopicListener topicListener) {
+        source.register(topicListener);
+    }
+
+    public boolean offer(String event) {
+        return source.offer(event);
+    }
+
+    public void unregister(TopicListener topicListener) {
+        source.unregister(topicListener);
+    }
+
+    /**
+     * Determines whether the topic is ready (i.e., {@link #awaitReady(Object, long)} has
+     * previously returned {@code true}).
+     *
+     * @return {@code true}, if the topic is ready to send and receive
+     */
+    public boolean isReady() {
+        return Boolean.TRUE.equals(checkerQueue.peek());
+    }
+
+    /**
+     * Waits for the bidirectional topic to become "ready" by publishing a message on the
+     * sink topic and awaiting receipt of the message on the source topic. If the message
+     * is not received within a few seconds, then it tries again. This process is
+     * continued until the message is received, {@link #stopWaiting()} is called, or this thread
+     * is interrupted. Once this returns, subsequent calls will return immediately, always
+     * with the same value.
+     *
+     * @param message message to be sent to the sink topic. Note: the equals() method must
+     *        return {@code true} if and only if two messages are the same
+     * @param waitMs time to wait, in milliseconds, before re-sending the message
+     * @return {@code true} if the message was received from the source topic,
+     *         {@code false} if this method was stopped or interrupted before receipt of
+     *         the message
+     * @throws CoderException if the message cannot be encoded
+     */
+    public synchronized <T> boolean awaitReady(T message, long waitMs) throws CoderException {
+        // see if we already know the answer
+        if (!checkerQueue.isEmpty()) {
+            return checkerQueue.peek();
+        }
+
+        final String messageText = coder.encode(message);
+
+        // class of message to be decoded
+        final TopicListener listener = getTopicListener(message);
+
+        source.register(listener);
+
+        // loop until the message is received
+        try {
+            Boolean result;
+            do {
+                send(messageText);
+            } while ((result = checkerQueue.poll(waitMs, TimeUnit.MILLISECONDS)) == null);
+
+            // put it back on the queue
+            checkerQueue.add(result);
+
+        } catch (InterruptedException e) {
+            logger.error("interrupted waiting for topic sink {} source {}", sink.getTopic(), source.getTopic(), e);
+            Thread.currentThread().interrupt();
+            checkerQueue.add(Boolean.FALSE);
+
+        } finally {
+            source.unregister(listener);
+        }
+
+        return checkerQueue.peek();
+    }
+
+    private <T> TopicListener getTopicListener(T message) {
+        @SuppressWarnings("unchecked")
+        final Class<? extends T> clazz = (Class<? extends T>) message.getClass();
+
+        // create a listener to detect when a matching message is received
+        return (infra, topic, msg) -> {
+            try {
+                T incoming = decode(msg, clazz);
+
+                if (message.equals(incoming)) {
+                    logger.info("topic {} is ready; found matching message {}", topic, incoming);
+                    checkerQueue.add(Boolean.TRUE);
+                }
+
+            } catch (CoderException e) {
+                logger.warn("cannot decode message from topic {}", topic, e);
+                decodeFailed();
+            }
+        };
+    }
+
+    /**
+     * Stops any listeners that are currently stuck in {@link #awaitReady(Object, long)} by
+     * adding {@code false} to the queue.
+     */
+    public void stopWaiting() {
+        checkerQueue.add(Boolean.FALSE);
+    }
+
+    // these may be overridden by junit tests
+
+    protected TopicEndpoint getTopicEndpointManager() {
+        return TopicEndpointManager.getManager();
+    }
+
+    protected <T> T decode(String msg, Class<? extends T> clazz) throws CoderException {
+        return coder.decode(msg, clazz);
+    }
+
+    protected void decodeFailed() {
+        // already logged - nothing else to do
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClientException.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClientException.java
new file mode 100644
index 00000000..442c5243
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClientException.java
@@ -0,0 +1,53 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2023-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.client;
+
+import java.io.Serial;
+
+/**
+ * Exception thrown by BidirectionalTopicClient class.
+ */
+public class BidirectionalTopicClientException extends Exception {
+    @Serial
+    private static final long serialVersionUID = 1L;
+
+    public BidirectionalTopicClientException() {
+        super();
+    }
+
+    public BidirectionalTopicClientException(String message) {
+        super(message);
+    }
+
+    public BidirectionalTopicClientException(Throwable cause) {
+        super(cause);
+    }
+
+    public BidirectionalTopicClientException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public BidirectionalTopicClientException(String message, Throwable cause, boolean enableSuppression,
+                    boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/TopicSinkClient.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/TopicSinkClient.java
new file mode 100644
index 00000000..131bf2d7
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/TopicSinkClient.java
@@ -0,0 +1,114 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2019, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.client;
+
+import java.util.List;
+import lombok.Getter;
+import lombok.NonNull;
+import org.onap.policy.common.message.bus.event.TopicEndpointManager;
+import org.onap.policy.common.message.bus.event.TopicSink;
+import org.onap.policy.common.utils.coder.Coder;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Client for sending messages to a Topic using TopicSink.
+ */
+@Getter
+public class TopicSinkClient {
+    private static final Logger logger = LoggerFactory.getLogger(TopicSinkClient.class);
+
+    /**
+     * Coder used to encode messages being sent to the topic.
+     */
+    private static final Coder CODER = new StandardCoder();
+
+    /**
+     * Where messages are published.
+     */
+    private final TopicSink sink;
+
+    /**
+     * Constructs the object.
+     *
+     * @param topic topic to which messages should be published
+     * @throws TopicSinkClientException if the topic does not exist
+     */
+    public TopicSinkClient(final String topic) throws TopicSinkClientException {
+        final List<TopicSink> lst = getTopicSinks(topic.toLowerCase());
+        if (lst.isEmpty()) {
+            throw new TopicSinkClientException("no sinks for topic: " + topic.toLowerCase());
+        }
+
+        this.sink = lst.get(0);
+    }
+
+    /**
+     * Constructs the client from a sink object.
+     *
+     * @param sink topic sink publisher
+     */
+    public TopicSinkClient(@NonNull TopicSink sink) {
+        this.sink = sink;
+    }
+
+
+    /**
+     * Gets the canonical topic name.
+     *
+     * @return topic name
+     */
+    public String getTopic() {
+        return this.sink.getTopic();
+    }
+
+    /**
+     * Sends a message to the topic, after encoding the message as json.
+     *
+     * @param message message to be encoded and sent
+     * @return {@code true} if the message was successfully sent/enqueued, {@code false} otherwise
+     */
+    public boolean send(final Object message) {
+        try {
+            final String json = CODER.encode(message);
+            return sink.send(json);
+
+        } catch (RuntimeException | CoderException e) {
+            logger.warn("send to {} failed because of {}", sink.getTopic(), e.getMessage(), e);
+            return false;
+        }
+    }
+
+    // the remaining methods are wrappers that can be overridden by junit tests
+
+    /**
+     * Gets the sinks for a given topic.
+     *
+     * @param topic the topic of interest
+     * @return the sinks for the topic
+     */
+    protected List<TopicSink> getTopicSinks(final String topic) {
+        return TopicEndpointManager.getManager().getTopicSinks(topic);
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/TopicSinkClientException.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/TopicSinkClientException.java
new file mode 100644
index 00000000..fad5e119
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/client/TopicSinkClientException.java
@@ -0,0 +1,54 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2019, 2023-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.client;
+
+import java.io.Serial;
+
+/**
+ * Exception thrown by TopicSink client classes.
+ */
+public class TopicSinkClientException extends Exception {
+    @Serial
+    private static final long serialVersionUID = 1L;
+
+    public TopicSinkClientException() {
+        super();
+    }
+
+    public TopicSinkClientException(final String message) {
+        super(message);
+    }
+
+    public TopicSinkClientException(final Throwable cause) {
+        super(cause);
+    }
+
+    public TopicSinkClientException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+
+    public TopicSinkClientException(final String message, final Throwable cause, final boolean enableSuppression,
+            final boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSinkFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSinkFactory.java
new file mode 100644
index 00000000..0497f1f5
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSinkFactory.java
@@ -0,0 +1,201 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_KAFKA_SINK_TOPICS;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SERVERS_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SINK_PARTITION_KEY_SUFFIX;
+
+import com.google.re2j.Pattern;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Properties;
+import org.apache.commons.lang3.StringUtils;
+import org.onap.policy.common.message.bus.utils.KafkaPropertyUtils;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.utils.properties.PropertyUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Factory of KAFKA Reader Topics indexed by topic name.
+ */
+class IndexedKafkaTopicSinkFactory implements KafkaTopicSinkFactory {
+    private static final Pattern COMMA_SPACE_PAT = Pattern.compile("\\s*,\\s*");
+    private static final String MISSING_TOPIC = "A topic must be provided";
+
+    /**
+     * Logger.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(IndexedKafkaTopicSinkFactory.class);
+
+    /**
+     * KAFKA Topic Name Index.
+     */
+    protected HashMap<String, KafkaTopicSink> kafkaTopicSinks = new HashMap<>();
+
+    @Override
+    public KafkaTopicSink build(BusTopicParams busTopicParams) {
+
+        if (busTopicParams.getServers() == null || busTopicParams.getServers().isEmpty()) {
+            throw new IllegalArgumentException("KAFKA Server(s) must be provided");
+        }
+
+        if (StringUtils.isBlank(busTopicParams.getTopic())) {
+            throw new IllegalArgumentException(MISSING_TOPIC);
+        }
+
+        synchronized (this) {
+            if (kafkaTopicSinks.containsKey(busTopicParams.getTopic())) {
+                return kafkaTopicSinks.get(busTopicParams.getTopic());
+            }
+
+            KafkaTopicSink kafkaTopicWriter = makeSink(busTopicParams);
+            if (busTopicParams.isManaged()) {
+                kafkaTopicSinks.put(busTopicParams.getTopic(), kafkaTopicWriter);
+            }
+
+            return kafkaTopicWriter;
+        }
+    }
+
+
+    @Override
+    public KafkaTopicSink build(List<String> servers, String topic) {
+        return this.build(BusTopicParams.builder()
+                .servers(servers)
+                .topic(topic)
+                .managed(true)
+                .useHttps(false)
+                .build());
+    }
+
+
+    @Override
+    public List<KafkaTopicSink> build(Properties properties) {
+
+        String writeTopics = properties.getProperty(PROPERTY_KAFKA_SINK_TOPICS);
+        if (StringUtils.isBlank(writeTopics)) {
+            logger.info("{}: no topic for KAFKA Sink", this);
+            return new ArrayList<>();
+        }
+
+        List<KafkaTopicSink> newKafkaTopicSinks = new ArrayList<>();
+        synchronized (this) {
+            for (String topic : COMMA_SPACE_PAT.split(writeTopics)) {
+                addTopic(newKafkaTopicSinks, topic.toLowerCase(), properties);
+            }
+            return newKafkaTopicSinks;
+        }
+    }
+
+    private void addTopic(List<KafkaTopicSink> newKafkaTopicSinks, String topic, Properties properties) {
+        if (this.kafkaTopicSinks.containsKey(topic)) {
+            newKafkaTopicSinks.add(this.kafkaTopicSinks.get(topic));
+            return;
+        }
+
+        String topicPrefix = PROPERTY_KAFKA_SINK_TOPICS + "." + topic;
+
+        var props = new PropertyUtils(properties, topicPrefix,
+            (name, value, ex) -> logger.warn("{}: {} {} is in invalid format for topic sink {} ",
+                this, name, value, topic));
+
+        String servers = properties.getProperty(topicPrefix + PROPERTY_TOPIC_SERVERS_SUFFIX);
+        if (StringUtils.isBlank(servers)) {
+            logger.error("{}: no KAFKA servers configured for sink {}", this, topic);
+            return;
+        }
+
+        KafkaTopicSink kafkaTopicWriter = this.build(KafkaPropertyUtils.makeBuilder(props, topic, servers)
+                .partitionId(props.getString(PROPERTY_TOPIC_SINK_PARTITION_KEY_SUFFIX, null))
+                .build());
+        newKafkaTopicSinks.add(kafkaTopicWriter);
+    }
+
+    @Override
+    public void destroy(String topic) {
+
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC);
+        }
+
+        KafkaTopicSink kafkaTopicWriter;
+        synchronized (this) {
+            if (!kafkaTopicSinks.containsKey(topic)) {
+                return;
+            }
+
+            kafkaTopicWriter = kafkaTopicSinks.remove(topic);
+        }
+
+        kafkaTopicWriter.shutdown();
+    }
+
+    @Override
+    public void destroy() {
+        List<KafkaTopicSink> writers = this.inventory();
+        for (KafkaTopicSink writer : writers) {
+            writer.shutdown();
+        }
+
+        synchronized (this) {
+            this.kafkaTopicSinks.clear();
+        }
+    }
+
+    @Override
+    public KafkaTopicSink get(String topic) {
+
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC);
+        }
+
+        synchronized (this) {
+            if (kafkaTopicSinks.containsKey(topic)) {
+                return kafkaTopicSinks.get(topic);
+            } else {
+                throw new IllegalStateException("KafkaTopicSink for " + topic + " not found");
+            }
+        }
+    }
+
+    @Override
+    public synchronized List<KafkaTopicSink> inventory() {
+        return new ArrayList<>(this.kafkaTopicSinks.values());
+    }
+
+    /**
+     * Makes a new sink.
+     *
+     * @param busTopicParams parameters to use to configure the sink
+     * @return a new sink
+     */
+    protected KafkaTopicSink makeSink(BusTopicParams busTopicParams) {
+        return new InlineKafkaTopicSink(busTopicParams);
+    }
+
+
+    @Override
+    public String toString() {
+        return "IndexedKafkaTopicSinkFactory " + kafkaTopicSinks.keySet();
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSourceFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSourceFactory.java
new file mode 100644
index 00000000..1aac89ce
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSourceFactory.java
@@ -0,0 +1,211 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.DEFAULT_LIMIT_FETCH;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.DEFAULT_TIMEOUT_MS_FETCH;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_KAFKA_SOURCE_TOPICS;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SERVERS_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SOURCE_CONSUMER_GROUP_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SOURCE_CONSUMER_INSTANCE_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SOURCE_FETCH_LIMIT_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SOURCE_FETCH_TIMEOUT_SUFFIX;
+
+import com.google.re2j.Pattern;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Properties;
+import org.apache.commons.lang3.StringUtils;
+import org.onap.policy.common.message.bus.utils.KafkaPropertyUtils;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.utils.properties.PropertyUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Factory of KAFKA Source Topics indexed by topic name.
+ */
+class IndexedKafkaTopicSourceFactory implements KafkaTopicSourceFactory {
+    private static final Pattern COMMA_SPACE_PAT = Pattern.compile("\\s*,\\s*");
+    private static final String MISSING_TOPIC = "A topic must be provided";
+
+    /**
+     * Logger.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(IndexedKafkaTopicSourceFactory.class);
+
+    /**
+     * KAFKA Topic Name Index.
+     */
+    protected HashMap<String, KafkaTopicSource> kafkaTopicSources = new HashMap<>();
+
+    @Override
+    public KafkaTopicSource build(BusTopicParams busTopicParams) {
+        if (busTopicParams.getServers() == null || busTopicParams.getServers().isEmpty()) {
+            throw new IllegalArgumentException("KAFKA Server(s) must be provided");
+        }
+
+        if (busTopicParams.getTopic() == null || busTopicParams.getTopic().isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC);
+        }
+
+        synchronized (this) {
+            if (kafkaTopicSources.containsKey(busTopicParams.getTopic())) {
+                return kafkaTopicSources.get(busTopicParams.getTopic());
+            }
+
+            var kafkaTopicSource = makeSource(busTopicParams);
+
+            kafkaTopicSources.put(busTopicParams.getTopic(), kafkaTopicSource);
+
+            return kafkaTopicSource;
+        }
+    }
+
+    @Override
+    public List<KafkaTopicSource> build(Properties properties) {
+
+        String readTopics = properties.getProperty(PROPERTY_KAFKA_SOURCE_TOPICS);
+        if (StringUtils.isBlank(readTopics)) {
+            logger.info("{}: no topic for KAFKA Source", this);
+            return new ArrayList<>();
+        }
+
+        List<KafkaTopicSource> newKafkaTopicSources = new ArrayList<>();
+        synchronized (this) {
+            for (String topic : COMMA_SPACE_PAT.split(readTopics)) {
+                addTopic(newKafkaTopicSources, topic.toLowerCase(), properties);
+            }
+        }
+        return newKafkaTopicSources;
+    }
+
+    @Override
+    public KafkaTopicSource build(List<String> servers, String topic) {
+        return this.build(BusTopicParams.builder()
+                .servers(servers)
+                .topic(topic)
+                .managed(true)
+                .fetchTimeout(DEFAULT_TIMEOUT_MS_FETCH)
+                .fetchLimit(DEFAULT_LIMIT_FETCH)
+                .useHttps(false).build());
+    }
+
+    private void addTopic(List<KafkaTopicSource> newKafkaTopicSources, String topic, Properties properties) {
+        if (this.kafkaTopicSources.containsKey(topic)) {
+            newKafkaTopicSources.add(this.kafkaTopicSources.get(topic));
+            return;
+        }
+
+        String topicPrefix = PROPERTY_KAFKA_SOURCE_TOPICS + "." + topic;
+
+        var props = new PropertyUtils(properties, topicPrefix,
+            (name, value, ex) -> logger.warn("{}: {} {} is in invalid format for topic source {} ",
+                this, name, value, topic));
+
+        String servers = properties.getProperty(topicPrefix + PROPERTY_TOPIC_SERVERS_SUFFIX);
+        if (StringUtils.isBlank(servers)) {
+            logger.error("{}: no KAFKA servers configured for source {}", this, topic);
+            return;
+        }
+
+        var kafkaTopicSource = this.build(KafkaPropertyUtils.makeBuilder(props, topic, servers)
+                .consumerGroup(props.getString(
+                        PROPERTY_TOPIC_SOURCE_CONSUMER_GROUP_SUFFIX, null))
+                .consumerInstance(props.getString(
+                        PROPERTY_TOPIC_SOURCE_CONSUMER_INSTANCE_SUFFIX, null))
+                .fetchTimeout(props.getInteger(
+                        PROPERTY_TOPIC_SOURCE_FETCH_TIMEOUT_SUFFIX,
+                        DEFAULT_TIMEOUT_MS_FETCH))
+                .fetchLimit(props.getInteger(PROPERTY_TOPIC_SOURCE_FETCH_LIMIT_SUFFIX,
+                        DEFAULT_LIMIT_FETCH))
+                .build());
+
+        newKafkaTopicSources.add(kafkaTopicSource);
+    }
+
+    /**
+     * Makes a new source.
+     *
+     * @param busTopicParams parameters to use to configure the source
+     * @return a new source
+     */
+    protected KafkaTopicSource makeSource(BusTopicParams busTopicParams) {
+        return new SingleThreadedKafkaTopicSource(busTopicParams);
+    }
+
+    @Override
+    public void destroy(String topic) {
+
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC);
+        }
+
+        KafkaTopicSource kafkaTopicSource;
+
+        synchronized (this) {
+            if (!kafkaTopicSources.containsKey(topic)) {
+                return;
+            }
+
+            kafkaTopicSource = kafkaTopicSources.remove(topic);
+        }
+
+        kafkaTopicSource.shutdown();
+    }
+
+    @Override
+    public void destroy() {
+        List<KafkaTopicSource> readers = this.inventory();
+        for (KafkaTopicSource reader : readers) {
+            reader.shutdown();
+        }
+
+        synchronized (this) {
+            this.kafkaTopicSources.clear();
+        }
+    }
+
+    @Override
+    public KafkaTopicSource get(String topic) {
+
+        if (topic == null || topic.isEmpty()) {
+            throw new IllegalArgumentException(MISSING_TOPIC);
+        }
+
+        synchronized (this) {
+            if (kafkaTopicSources.containsKey(topic)) {
+                return kafkaTopicSources.get(topic);
+            } else {
+                throw new IllegalStateException("KafkaTopiceSource for " + topic + " not found");
+            }
+        }
+    }
+
+    @Override
+    public synchronized List<KafkaTopicSource> inventory() {
+        return new ArrayList<>(this.kafkaTopicSources.values());
+    }
+
+    @Override
+    public String toString() {
+        return "IndexedKafkaTopicSourceFactory " + kafkaTopicSources.keySet();
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/InlineKafkaTopicSink.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/InlineKafkaTopicSink.java
new file mode 100644
index 00000000..4bdd2b0f
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/InlineKafkaTopicSink.java
@@ -0,0 +1,83 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import java.util.Map;
+import org.onap.policy.common.message.bus.event.Topic;
+import org.onap.policy.common.message.bus.event.base.InlineBusTopicSink;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This implementation publishes events for the associated KAFKA topic, inline with the calling
+ * thread.
+ */
+public class InlineKafkaTopicSink extends InlineBusTopicSink implements KafkaTopicSink {
+
+    /**
+     * Logger.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(InlineKafkaTopicSink.class);
+
+    protected Map<String, String> additionalProps;
+
+    /**
+     * Argument-based KAFKA Topic Writer instantiation. BusTopicParams contains the below
+     * attributes.
+     *
+     * <p>servers              list of KAFKA servers available for publishing
+     * topic                the topic to publish to
+     * partitionId          the partition key (optional, autogenerated if not provided)
+     * useHttps             does connection use HTTPS?
+     * @param busTopicParams contains attributes needed
+     * @throws IllegalArgumentException if invalid arguments are detected
+     */
+    public InlineKafkaTopicSink(BusTopicParams busTopicParams) {
+        super(busTopicParams);
+        this.additionalProps = busTopicParams.getAdditionalProps();
+    }
+
+    /**
+     * Instantiation of internal resources.
+     */
+    @Override
+    public void init() {
+
+        this.publisher = new KafkaPublisherWrapper(BusTopicParams.builder()
+                .servers(this.servers)
+                .topic(this.effectiveTopic)
+                .useHttps(this.useHttps)
+                .allowTracing(this.allowTracing)
+                .additionalProps(this.additionalProps)
+                .build());
+        logger.info("{}: KAFKA SINK created", this);
+    }
+
+    @Override
+    public String toString() {
+        return "InlineKafkaTopicSink [getTopicCommInfrastructure()=" + getTopicCommInfrastructure() + ", toString()="
+                        + super.toString() + "]";
+    }
+
+    @Override
+    public CommInfrastructure getTopicCommInfrastructure() {
+        return Topic.CommInfrastructure.KAFKA;
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaPublisherWrapper.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaPublisherWrapper.java
new file mode 100644
index 00000000..86b9e936
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaPublisherWrapper.java
@@ -0,0 +1,121 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import io.opentelemetry.instrumentation.kafkaclients.v2_6.TracingProducerInterceptor;
+import java.util.Properties;
+import java.util.UUID;
+import org.apache.kafka.clients.producer.KafkaProducer;
+import org.apache.kafka.clients.producer.Producer;
+import org.apache.kafka.clients.producer.ProducerConfig;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.onap.policy.common.message.bus.event.base.BusPublisher;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Kafka based library publisher.
+ */
+public class KafkaPublisherWrapper implements BusPublisher {
+
+    private static final Logger logger = LoggerFactory.getLogger(KafkaPublisherWrapper.class);
+    private static final String KEY_SERIALIZER = "org.apache.kafka.common.serialization.StringSerializer";
+
+    private final String topic;
+
+    /**
+     * Kafka publisher.
+     */
+    private final Producer<String, String> producer;
+    protected Properties kafkaProps;
+
+    /**
+     * Kafka Publisher Wrapper.
+     *
+     * @param busTopicParams topic parameters
+     */
+    public KafkaPublisherWrapper(BusTopicParams busTopicParams) {
+
+        if (busTopicParams.isTopicInvalid()) {
+            throw new IllegalArgumentException("No topic for Kafka");
+        }
+
+        this.topic = busTopicParams.getTopic();
+
+        // Setup Properties for consumer
+        kafkaProps = new Properties();
+        kafkaProps.setProperty(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, busTopicParams.getServers().get(0));
+        if (busTopicParams.isAdditionalPropsValid()) {
+            kafkaProps.putAll(busTopicParams.getAdditionalProps());
+        }
+
+        if (kafkaProps.get(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG) == null) {
+            kafkaProps.setProperty(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, KEY_SERIALIZER);
+        }
+
+        if (kafkaProps.get(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG) == null) {
+            kafkaProps.setProperty(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, KEY_SERIALIZER);
+        }
+
+        if (busTopicParams.isAllowTracing()) {
+            kafkaProps.setProperty(ProducerConfig.INTERCEPTOR_CLASSES_CONFIG,
+                TracingProducerInterceptor.class.getName());
+        }
+
+        producer = new KafkaProducer<>(kafkaProps);
+    }
+
+    @Override
+    public boolean send(String partitionId, String message) {
+        if (message == null) {
+            throw new IllegalArgumentException(NO_MESSAGE_PROVIDED);
+        }
+
+        try {
+            // Create the record
+            ProducerRecord<String, String> producerRecord =
+                new ProducerRecord<>(topic, UUID.randomUUID().toString(), message);
+
+            this.producer.send(producerRecord);
+            producer.flush();
+        } catch (Exception e) {
+            logger.warn("{}: SEND of {} cannot be performed because of {}", this, message, e.getMessage(), e);
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public void close() {
+        logger.info(LOG_CLOSE, this);
+
+        try {
+            this.producer.close();
+        } catch (Exception e) {
+            logger.warn("{}: CLOSE FAILED because of {}", this, e.getMessage(), e);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "KafkaPublisherWrapper []";
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicFactories.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicFactories.java
new file mode 100644
index 00000000..c10285fc
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicFactories.java
@@ -0,0 +1,39 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class KafkaTopicFactories {
+
+    /**
+     * Factory for instantiation and management of sinks.
+     */
+    @Getter
+    private static final KafkaTopicSinkFactory sinkFactory = new IndexedKafkaTopicSinkFactory();
+
+    /**
+     * Factory for instantiation and management of sources.
+     */
+    @Getter
+    private static final KafkaTopicSourceFactory sourceFactory = new IndexedKafkaTopicSourceFactory();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSink.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSink.java
new file mode 100644
index 00000000..f784a987
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSink.java
@@ -0,0 +1,28 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import org.onap.policy.common.message.bus.event.base.BusTopicSink;
+
+/**
+ * Topic Writer over KAFKA Infrastructure.
+ */
+public interface KafkaTopicSink extends BusTopicSink {
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkFactory.java
new file mode 100644
index 00000000..8feecbe0
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkFactory.java
@@ -0,0 +1,89 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+/**
+ * KAFKA Topic Sink Factory.
+ */
+public interface KafkaTopicSinkFactory {
+
+    /**
+     * Instantiates a new KAFKA Topic Writer.
+     *
+     * @param busTopicParams parameters object
+     * @return an KAFKA Topic Sink
+     */
+    KafkaTopicSink build(BusTopicParams busTopicParams);
+
+    /**
+     * Creates an KAFKA Topic Writer based on properties files.
+     *
+     * @param properties Properties containing initialization values
+     *
+     * @return an KAFKA Topic Writer
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    List<KafkaTopicSink> build(Properties properties);
+
+    /**
+     * Instantiates a new KAFKA Topic Writer.
+     *
+     * @param servers list of servers
+     * @param topic topic name
+     *
+     * @return an KAFKA Topic Writer
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    KafkaTopicSink build(List<String> servers, String topic);
+
+    /**
+     * Destroys an KAFKA Topic Writer based on a topic.
+     *
+     * @param topic topic name
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    void destroy(String topic);
+
+    /**
+     * Destroys all KAFKA Topic Writers.
+     */
+    void destroy();
+
+    /**
+     * gets an KAFKA Topic Writer based on topic name.
+     *
+     * @param topic the topic name
+     *
+     * @return an KAFKA Topic Writer with topic name
+     * @throws IllegalArgumentException if an invalid topic is provided
+     * @throws IllegalStateException if the KAFKA Topic Reader is an incorrect state
+     */
+    KafkaTopicSink get(String topic);
+
+    /**
+     * Provides a snapshot of the KAFKA Topic Writers.
+     *
+     * @return a list of the KAFKA Topic Writers
+     */
+    List<KafkaTopicSink> inventory();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSource.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSource.java
new file mode 100644
index 00000000..bddced7a
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSource.java
@@ -0,0 +1,28 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import org.onap.policy.common.message.bus.event.base.BusTopicSource;
+
+/**
+ * Kafka Topic Source.
+ */
+public interface KafkaTopicSource extends BusTopicSource {
+
+}
\ No newline at end of file
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceFactory.java
new file mode 100644
index 00000000..06f4412c
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceFactory.java
@@ -0,0 +1,88 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+/**
+ * Kafka Topic Source Factory.
+ */
+public interface KafkaTopicSourceFactory {
+
+    /**
+     * Creates a Kafka Topic Source based on properties files.
+     *
+     * @param properties Properties containing initialization values
+     *
+     * @return a Kafka Topic Source
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    List<KafkaTopicSource> build(Properties properties);
+
+    /**
+     * Instantiates a new Kafka Topic Source.
+     *
+     * @param busTopicParams parameters object
+     * @return a Kafka Topic Source
+     */
+    KafkaTopicSource build(BusTopicParams busTopicParams);
+
+    /**
+     * Instantiates a new Kafka Topic Source.
+     *
+     * @param servers list of servers
+     * @param topic topic name
+     *
+     * @return a Kafka Topic Source
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    KafkaTopicSource build(List<String> servers, String topic);
+
+    /**
+     * Destroys a Kafka Topic Source based on a topic.
+     *
+     * @param topic topic name
+     * @throws IllegalArgumentException if invalid parameters are present
+     */
+    void destroy(String topic);
+
+    /**
+     * Destroys all Kafka Topic Sources.
+     */
+    void destroy();
+
+    /**
+     * Gets a Kafka Topic Source based on topic name.
+     *
+     * @param topic the topic name
+     * @return a Kafka Topic Source with topic name
+     * @throws IllegalArgumentException if an invalid topic is provided
+     * @throws IllegalStateException if the Kafka Topic Source is an incorrect state
+     */
+    KafkaTopicSource get(String topic);
+
+    /**
+     * Provides a snapshot of the Kafka Topic Sources.
+     *
+     * @return a list of the Kafka Topic Sources
+     */
+    List<KafkaTopicSource> inventory();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/SingleThreadedKafkaTopicSource.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/SingleThreadedKafkaTopicSource.java
new file mode 100644
index 00000000..5691cb12
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/kafka/SingleThreadedKafkaTopicSource.java
@@ -0,0 +1,80 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import java.util.Map;
+import org.onap.policy.common.message.bus.event.Topic;
+import org.onap.policy.common.message.bus.event.base.BusConsumer;
+import org.onap.policy.common.message.bus.event.base.SingleThreadedBusTopicSource;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+/**
+ * This topic source implementation specializes in reading messages over a Kafka Bus topic source and
+ * notifying its listeners.
+ */
+public class SingleThreadedKafkaTopicSource extends SingleThreadedBusTopicSource implements KafkaTopicSource {
+
+    protected Map<String, String> additionalProps = null;
+
+    /**
+     * Constructor.
+     *
+     * @param busTopicParams Parameters object containing all the required inputs
+     * @throws IllegalArgumentException An invalid parameter passed in
+     */
+    public SingleThreadedKafkaTopicSource(BusTopicParams busTopicParams) {
+        super(busTopicParams);
+        this.additionalProps = busTopicParams.getAdditionalProps();
+        try {
+            this.init();
+        } catch (Exception e) {
+            throw new IllegalArgumentException("ERROR during init in kafka-source: cannot create topic " + topic, e);
+        }
+    }
+
+    /**
+     * Initialize the client.
+     */
+    @Override
+    public void init() {
+        BusTopicParams.TopicParamsBuilder builder = BusTopicParams.builder()
+                .servers(this.servers)
+                .topic(this.effectiveTopic)
+                .fetchTimeout(this.fetchTimeout)
+                .consumerGroup(this.consumerGroup)
+                .useHttps(this.useHttps)
+                .allowTracing(this.allowTracing);
+
+        this.consumer = new BusConsumer.KafkaConsumerWrapper(builder
+                        .additionalProps(this.additionalProps)
+                        .build());
+    }
+
+    @Override
+    public CommInfrastructure getTopicCommInfrastructure() {
+        return Topic.CommInfrastructure.KAFKA;
+    }
+
+    @Override
+    public String toString() {
+        return "SingleThreadedKafkaTopicSource [getTopicCommInfrastructure()=" + getTopicCommInfrastructure()
+            + ", toString()=" + super.toString() + "]";
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicEndpoint.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicEndpoint.java
new file mode 100644
index 00000000..e25aca54
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicEndpoint.java
@@ -0,0 +1,141 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2019 Samsung Electronics Co., Ltd.
+ * Modifications Copyright (C) 2020 Bell Canada. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import java.util.List;
+import org.onap.policy.common.message.bus.event.base.TopicBase;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * No Operation topic endpoint.
+ */
+public abstract class NoopTopicEndpoint extends TopicBase {
+
+    /**
+     * Logger.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(NoopTopicEndpoint.class);
+
+    /**
+     * Constructs the object.
+     */
+    protected NoopTopicEndpoint(List<String> servers, String topic) {
+        super(servers, topic);
+    }
+
+    /**
+     *  I/O.
+     *
+     * @param type "IN" or "OUT".
+     * @param message message.
+     * @return true if successful.
+     */
+    protected boolean io(EventType type, String message) {
+
+        if (message == null || message.isEmpty()) {
+            throw new IllegalArgumentException("Message is empty");
+        }
+
+        if (!this.alive) {
+            throw new IllegalStateException(this + " is stopped");
+        }
+
+        try {
+            synchronized (this) {
+                this.recentEvents.add(message);
+            }
+
+            NetLoggerUtil.log(type, this.getTopicCommInfrastructure(), this.topic, message);
+
+            broadcast(message);
+        } catch (Exception e) {
+            logger.warn("{}: cannot send because of {}", this, e.getMessage(), e);
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public CommInfrastructure getTopicCommInfrastructure() {
+        return CommInfrastructure.NOOP;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean start() {
+        logger.info("{}: starting", this);
+
+        synchronized (this) {
+            if (!this.alive) {
+                if (locked) {
+                    throw new IllegalStateException(this + " is locked.");
+                }
+
+                this.alive = true;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean stop() {
+        logger.info("{}: stopping", this);
+
+        synchronized (this) {
+            this.alive = false;
+        }
+        return true;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public void shutdown() {
+        logger.info("{}: shutdown", this);
+
+        this.stop();
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "NoopTopicEndpoint[" + super.toString() + "]";
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactories.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactories.java
new file mode 100644
index 00000000..506cc9f9
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactories.java
@@ -0,0 +1,42 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class NoopTopicFactories {
+
+    /**
+     * Factory for instantiation and management of sinks.
+     */
+    @Getter
+    private static final NoopTopicSinkFactory sinkFactory = new NoopTopicSinkFactory();
+
+    /**
+     * Factory for instantiation and management of sources.
+     */
+    @Getter
+    private static final NoopTopicSourceFactory sourceFactory = new NoopTopicSourceFactory();
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactory.java
new file mode 100644
index 00000000..e81dfaea
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactory.java
@@ -0,0 +1,117 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_MANAGED_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SERVERS_SUFFIX;
+
+import com.google.re2j.Pattern;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.base.TopicBaseHashedFactory;
+
+/**
+ * Noop Topic Factory.
+ */
+public abstract class NoopTopicFactory<T extends NoopTopicEndpoint> extends TopicBaseHashedFactory<T> {
+    private static final Pattern COMMA_SPACE_PAT = Pattern.compile("\\s*,\\s*");
+
+    /**
+     * Get Topics Property Name.
+     *
+     * @return property name.
+     */
+    protected abstract String getTopicsPropertyName();
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    protected List<String> getTopicNames(Properties properties) {
+        String topics = properties.getProperty(getTopicsPropertyName());
+        if (topics == null || topics.isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        return Arrays.asList(COMMA_SPACE_PAT.split(topics));
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    protected List<String> getServers(String topicName, Properties properties) {
+        String servers =
+            properties.getProperty(getTopicsPropertyName() + "." + topicName
+                + PROPERTY_TOPIC_SERVERS_SUFFIX);
+
+        if (servers == null || servers.isEmpty()) {
+            servers = CommInfrastructure.NOOP.toString();
+        }
+
+        return new ArrayList<>(Arrays.asList(COMMA_SPACE_PAT.split(servers)));
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    protected boolean isManaged(String topicName, Properties properties) {
+        var managedString =
+            properties.getProperty(getTopicsPropertyName() + "." + topicName + PROPERTY_MANAGED_SUFFIX);
+
+        var managed = true;
+        if (managedString != null && !managedString.isEmpty()) {
+            managed = Boolean.parseBoolean(managedString);
+        }
+
+        return managed;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public T build(List<String> serverList, String topic, boolean managed) {
+        List<String> servers;
+        if (serverList == null || serverList.isEmpty()) {
+            servers = Collections.singletonList(CommInfrastructure.NOOP.toString());
+        } else {
+            servers = serverList;
+        }
+
+        return super.build(servers, topic, managed);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "NoopTopicFactory[ " + super.toString() + " ]";
+    }
+}
+
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSink.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSink.java
new file mode 100644
index 00000000..b7d78ff4
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSink.java
@@ -0,0 +1,56 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import java.util.List;
+import org.onap.policy.common.message.bus.event.TopicSink;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+
+/**
+ * No Operation Topic Sink.
+ */
+public class NoopTopicSink extends NoopTopicEndpoint implements TopicSink {
+
+    /**
+     * Constructs the object.
+     */
+    public NoopTopicSink(List<String> servers, String topic) {
+        super(servers, topic);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean send(String message) {
+        return super.io(EventType.OUT, message);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "NoopTopicSink[" + super.toString() + "]";
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkFactory.java
new file mode 100644
index 00000000..cdf4a17b
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkFactory.java
@@ -0,0 +1,58 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_NOOP_SINK_TOPICS;
+
+import java.util.List;
+
+/**
+ * Noop Topic Sink Factory.
+ */
+public class NoopTopicSinkFactory extends NoopTopicFactory<NoopTopicSink> {
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    protected String getTopicsPropertyName() {
+        return PROPERTY_NOOP_SINK_TOPICS;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public NoopTopicSink build(List<String> servers, String topic) {
+        return new NoopTopicSink(servers, topic);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "NoopTopicSinkFactory [" + super.toString() + "]";
+    }
+
+}
+
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSource.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSource.java
new file mode 100644
index 00000000..6e7d0216
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSource.java
@@ -0,0 +1,56 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import java.util.List;
+import org.onap.policy.common.message.bus.event.TopicSource;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+
+/**
+ * No Operation Topic Source.
+ */
+public class NoopTopicSource extends NoopTopicEndpoint implements TopicSource {
+
+    /**
+     * Constructs the object.
+     */
+    public NoopTopicSource(List<String> servers, String topic) {
+        super(servers, topic);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public boolean offer(String event) {
+        return super.io(EventType.IN, event);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "NoopTopicSource[" + super.toString() + "]";
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceFactory.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceFactory.java
new file mode 100644
index 00000000..5e3a365a
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceFactory.java
@@ -0,0 +1,56 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_NOOP_SOURCE_TOPICS;
+
+import java.util.List;
+
+/**
+ * No Operation Topic Source Factory.
+ */
+public class NoopTopicSourceFactory extends NoopTopicFactory<NoopTopicSource> {
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    protected String getTopicsPropertyName() {
+        return PROPERTY_NOOP_SOURCE_TOPICS;
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public NoopTopicSource build(List<String> servers, String topic) {
+        return new NoopTopicSource(servers, topic);
+    }
+
+    /**
+     * {@inheritDoc}.
+     */
+    @Override
+    public String toString() {
+        return "NoopTopicSourceFactory [" + super.toString() + "]";
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureApi.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureApi.java
new file mode 100644
index 00000000..6e3b8301
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureApi.java
@@ -0,0 +1,54 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.features;
+
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+import org.onap.policy.common.utils.services.OrderedService;
+import org.slf4j.Logger;
+
+/**
+ * Logging Feature API. Provides interception points before and after logging a message.
+ */
+public interface NetLoggerFeatureApi extends OrderedService {
+
+    /**
+     * Intercepts a message before it is logged.
+     *
+     * @return true if this feature intercepts and takes ownership of the operation
+     *         preventing the invocation of lower priority features. False, otherwise.
+     */
+    default boolean beforeLog(Logger eventLogger, EventType type, CommInfrastructure protocol, String topic,
+                    String message) {
+        return false;
+    }
+
+    /**
+     * Intercepts a message after it is logged.
+     *
+     * @return true if this feature intercepts and takes ownership of the operation
+     *         preventing the invocation of lower priority features. False, otherwise.
+     */
+    default boolean afterLog(Logger eventLogger, EventType type, CommInfrastructure protocol, String topic,
+                    String message) {
+        return false;
+    }
+
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureProviders.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureProviders.java
new file mode 100644
index 00000000..4f57ab2a
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureProviders.java
@@ -0,0 +1,41 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.features;
+
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import org.onap.policy.common.utils.services.OrderedServiceImpl;
+
+/**
+ * Providers for network logging feature.
+ */
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class NetLoggerFeatureProviders {
+
+    /**
+     * Feature providers implementing this interface.
+     */
+    @Getter
+    private static final OrderedServiceImpl<NetLoggerFeatureApi> providers =
+                    new OrderedServiceImpl<>(NetLoggerFeatureApi.class);
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/properties/MessageBusProperties.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/properties/MessageBusProperties.java
new file mode 100644
index 00000000..9aa529f3
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/properties/MessageBusProperties.java
@@ -0,0 +1,78 @@
+/*-
+ * ============LICENSE_START===============================================
+ * Copyright (C) 2024 Nordix Foundation.
+ * ========================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=================================================
+ */
+
+package org.onap.policy.common.message.bus.properties;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public final class MessageBusProperties {
+
+    /* Generic property suffixes */
+
+    public static final String PROPERTY_TOPIC_SERVERS_SUFFIX = ".servers";
+    public static final String PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX = ".effectiveTopic";
+
+    public static final String PROPERTY_TOPIC_SOURCE_CONSUMER_GROUP_SUFFIX = ".consumerGroup";
+    public static final String PROPERTY_TOPIC_SOURCE_CONSUMER_INSTANCE_SUFFIX = ".consumerInstance";
+    public static final String PROPERTY_TOPIC_SOURCE_FETCH_TIMEOUT_SUFFIX = ".fetchTimeout";
+    public static final String PROPERTY_TOPIC_SOURCE_FETCH_LIMIT_SUFFIX = ".fetchLimit";
+    public static final String PROPERTY_MANAGED_SUFFIX = ".managed";
+    public static final String PROPERTY_ADDITIONAL_PROPS_SUFFIX = ".additionalProps";
+
+    public static final String PROPERTY_TOPIC_SINK_PARTITION_KEY_SUFFIX = ".partitionKey";
+
+    public static final String PROPERTY_ALLOW_SELF_SIGNED_CERTIFICATES_SUFFIX = ".selfSignedCertificates";
+
+    public static final String PROPERTY_NOOP_SOURCE_TOPICS = "noop.source.topics";
+    public static final String PROPERTY_NOOP_SINK_TOPICS = "noop.sink.topics";
+
+    /* KAFKA Properties */
+
+    public static final String PROPERTY_KAFKA_SOURCE_TOPICS = "kafka.source.topics";
+    public static final String PROPERTY_KAFKA_SINK_TOPICS = "kafka.sink.topics";
+
+    /* HTTP Server Properties */
+
+    public static final String PROPERTY_HTTP_HTTPS_SUFFIX = ".https";
+
+    /* Topic Sink Values */
+
+    /* Topic Source values */
+
+    /**
+     * Default Timeout fetching in milliseconds.
+     */
+    public static final int DEFAULT_TIMEOUT_MS_FETCH = 15000;
+
+    /**
+     * Default maximum number of messages fetch at the time.
+     */
+    public static final int DEFAULT_LIMIT_FETCH = 100;
+
+    /**
+     * Definition of No Timeout fetching.
+     */
+    public static final int NO_TIMEOUT_MS_FETCH = -1;
+
+    /**
+     * Definition of No limit fetching.
+     */
+    public static final int NO_LIMIT_FETCH = -1;
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/utils/KafkaPropertyUtils.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/utils/KafkaPropertyUtils.java
new file mode 100644
index 00000000..cfe62208
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/utils/KafkaPropertyUtils.java
@@ -0,0 +1,80 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.utils;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_ADDITIONAL_PROPS_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_MANAGED_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.re2j.Pattern;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.parameters.topic.BusTopicParams.TopicParamsBuilder;
+import org.onap.policy.common.utils.properties.PropertyUtils;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class KafkaPropertyUtils {
+    private static final Pattern COMMA_SPACE_PAT = Pattern.compile("\\s*,\\s*");
+
+    /**
+     * Makes a topic builder, configuring it with properties that are common to both
+     * sources and sinks.
+     *
+     * @param props   properties to be used to configure the builder
+     * @param topic   topic being configured
+     * @param servers target servers
+     * @return a topic builder
+     */
+    public static TopicParamsBuilder makeBuilder(PropertyUtils props, String topic, String servers) {
+
+        final List<String> serverList = new ArrayList<>(Arrays.asList(COMMA_SPACE_PAT.split(servers)));
+        return BusTopicParams.builder()
+            .servers(serverList)
+            .topic(topic)
+            .effectiveTopic(props.getString(PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX, topic))
+            .managed(props.getBoolean(PROPERTY_MANAGED_SUFFIX, true))
+            .additionalProps(getAdditionalProps(props.getString(PROPERTY_ADDITIONAL_PROPS_SUFFIX, "")));
+    }
+
+    private static Map<String, String> getAdditionalProps(String additionalPropsString) {
+        try {
+            Map<String, String> additionalProps = new HashMap<>();
+            var converted = new ObjectMapper().readValue(additionalPropsString, Map.class);
+            converted.forEach((k, v) -> {
+                if (k instanceof String key && v instanceof String value) {
+                    additionalProps.put(key, value);
+                }
+            });
+            return additionalProps;
+        } catch (Exception e) {
+            return Collections.emptyMap();
+        }
+
+    }
+}
diff --git a/message-bus/src/main/java/org/onap/policy/common/message/bus/utils/NetLoggerUtil.java b/message-bus/src/main/java/org/onap/policy/common/message/bus/utils/NetLoggerUtil.java
new file mode 100644
index 00000000..b5454e5c
--- /dev/null
+++ b/message-bus/src/main/java/org/onap/policy/common/message/bus/utils/NetLoggerUtil.java
@@ -0,0 +1,134 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.utils;
+
+import lombok.Getter;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.features.NetLoggerFeatureProviders;
+import org.onap.policy.common.utils.services.FeatureApiUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A network logging utility class that allows drools applications code to access the
+ * network log (or other specified loggers) and logging features.
+ *
+ */
+public class NetLoggerUtil {
+
+    /**
+     * Loggers.
+     */
+    private static final Logger logger = LoggerFactory.getLogger(NetLoggerUtil.class);
+    @Getter
+    private static final Logger networkLogger = LoggerFactory.getLogger("network");
+
+    /**
+     * Constant for the system line separator.
+     */
+    public static final String SYSTEM_LS = System.lineSeparator();
+
+    /**
+     * Specifies if the message is coming in or going out.
+     */
+    public enum EventType {
+        IN, OUT
+    }
+
+    /**
+     * Logs a message to the network logger.
+     *
+     * @param type can either be IN or OUT
+     * @param protocol the protocol used to receive/send the message
+     * @param topic the topic the message came from or null if the type is REST
+     * @param message message to be logged
+     */
+    public static void log(EventType type, CommInfrastructure protocol, String topic, String message) {
+        log(networkLogger, type, protocol, topic, message);
+    }
+
+    /**
+     * Logs a message to the specified logger (i.e. a controller logger).
+     *
+     * @param eventLogger the logger that will have the message appended
+     * @param type can either be IN or OUT
+     * @param protocol the protocol used to receive/send the message
+     * @param topic the topic the message came from or null if the type is REST
+     * @param message message to be logged
+     */
+    public static void log(Logger eventLogger, EventType type, CommInfrastructure protocol, String topic,
+                    String message) {
+        if (eventLogger == null) {
+            logger.debug("the logger is null, defaulting to network logger");
+            eventLogger = networkLogger;
+        }
+
+        if (featureBeforeLog(eventLogger, type, protocol, topic, message)) {
+            return;
+        }
+
+        eventLogger.info("[{}|{}|{}]{}{}", type, protocol, topic, SYSTEM_LS, message);
+
+        featureAfterLog(eventLogger, type, protocol, topic, message);
+    }
+
+    /**
+     * Executes features that pre-process a message before it is logged.
+     *
+     * @param eventLogger the logger that will have the message appended
+     * @param type can either be IN or OUT
+     * @param protocol the protocol used to receive/send the message
+     * @param topic the topic the message came from or null if the type is REST
+     * @param message message to be logged
+     *
+     * @return true if this feature intercepts and takes ownership of the operation
+     *         preventing the invocation of lower priority features. False, otherwise
+     */
+    private static boolean featureBeforeLog(Logger eventLogger, EventType type, CommInfrastructure protocol,
+                    String topic, String message) {
+
+        return FeatureApiUtils.apply(NetLoggerFeatureProviders.getProviders().getList(),
+            feature -> feature.beforeLog(eventLogger, type, protocol, topic, message),
+            (feature, ex) -> logger.error("feature {} before-log failure because of {}",
+                            feature.getClass().getName(), ex.getMessage(), ex));
+    }
+
+    /**
+     * Executes features that post-process a message after it is logged.
+     *
+     * @param eventLogger the logger that will have the message appended
+     * @param type can either be IN or OUT
+     * @param protocol the protocol used to receive/send the message
+     * @param topic the topic the message came from or null if the type is rest
+     * @param message message to be logged
+     *
+     * @return true if this feature intercepts and takes ownership of the operation
+     *         preventing the invocation of lower priority features. False, otherwise
+     */
+    private static boolean featureAfterLog(Logger eventLogger, EventType type, CommInfrastructure protocol,
+                    String topic, String message) {
+
+        return FeatureApiUtils.apply(NetLoggerFeatureProviders.getProviders().getList(),
+            feature -> feature.afterLog(eventLogger, type, protocol, topic, message),
+            (feature, ex) -> logger.error("feature {} after-log failure because of {}",
+                            feature.getClass().getName(), ex.getMessage(), ex));
+    }
+
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/CommonTestData.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/CommonTestData.java
new file mode 100644
index 00000000..ecd2f20c
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/CommonTestData.java
@@ -0,0 +1,111 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2019, 2024 Nordix Foundation.
+ *  Modifications Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import org.onap.policy.common.parameters.ParameterGroup;
+import org.onap.policy.common.parameters.topic.TopicParameters;
+import org.onap.policy.common.utils.coder.Coder;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
+
+/**
+ * Class to hold/create all parameters for test cases.
+ *
+ * @author Ajith Sreekumar (ajith.sreekumar@est.tech)
+ */
+public class CommonTestData {
+
+    public static final String TOPIC_NAME = "policy-pdp-pap";
+    public static final String TOPIC_INFRA = "kafka";
+    public static final String TOPIC_SERVER = "kafka:9092";
+
+    public static final List<TopicParameters> TOPIC_PARAMS =
+        List.of(getTopicParameters(TOPIC_NAME, TOPIC_INFRA, TOPIC_SERVER));
+
+    protected static final Coder coder = new StandardCoder();
+
+    /**
+     * Create topic parameters for test cases.
+     *
+     * @param topicName   name of topic
+     * @param topicInfra  topicCommInfrastructure
+     * @param topicServer topic server
+     * @return topic parameters
+     */
+    public static TopicParameters getTopicParameters(String topicName, String topicInfra, String topicServer) {
+        final TopicParameters topicParams = new TopicParameters();
+        topicParams.setTopic(topicName);
+        topicParams.setTopicCommInfrastructure(topicInfra);
+        topicParams.setServers(List.of(topicServer));
+        return topicParams;
+    }
+
+    /**
+     * Converts the contents of a map to a parameter class.
+     *
+     * @param source property map
+     * @param clazz  class of object to be created from the map
+     * @return a new object represented by the map
+     */
+    public <T extends ParameterGroup> T toObject(final Map<String, Object> source, final Class<T> clazz) {
+        try {
+            return coder.decode(coder.encode(source), clazz);
+
+        } catch (final CoderException e) {
+            throw new RuntimeException("cannot create " + clazz.getName() + " from map", e);
+        }
+    }
+
+    /**
+     * Returns a property map for a TopicParameters map for test cases.
+     *
+     * @param isEmpty boolean value to represent that object created should be empty or not
+     * @return a property map suitable for constructing an object
+     */
+    public Map<String, Object> getTopicParameterGroupMap(final boolean isEmpty) {
+        final Map<String, Object> map = new TreeMap<>();
+        if (!isEmpty) {
+            map.put("topicSources", TOPIC_PARAMS);
+            map.put("topicSinks", TOPIC_PARAMS);
+        }
+
+        return map;
+    }
+
+    /**
+     * Gets the standard parameter group as a String.
+     *
+     * @param filePath path of the file
+     * @return the standard parameters
+     * @throws IOException when file read operation fails
+     */
+    public String getParameterGroupAsString(String filePath) throws IOException {
+        File file = new File(filePath);
+        return Files.readString(file.toPath());
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/TopicEndpointProxyTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/TopicEndpointProxyTest.java
new file mode 100644
index 00000000..6f0e38dd
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/TopicEndpointProxyTest.java
@@ -0,0 +1,400 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Properties;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.kafka.KafkaTopicFactories;
+import org.onap.policy.common.message.bus.event.kafka.KafkaTopicPropertyBuilder;
+import org.onap.policy.common.message.bus.event.noop.NoopTopicFactories;
+import org.onap.policy.common.message.bus.event.noop.NoopTopicPropertyBuilder;
+import org.onap.policy.common.message.bus.properties.MessageBusProperties;
+import org.onap.policy.common.parameters.topic.TopicParameterGroup;
+import org.onap.policy.common.parameters.topic.TopicParameters;
+import org.onap.policy.common.utils.gson.GsonTestUtils;
+
+class TopicEndpointProxyTest {
+
+    private static final String NOOP_SOURCE_TOPIC = "noop-source";
+    private static final String NOOP_SINK_TOPIC = "noop-sink";
+
+    private static final String KAFKA_SOURCE_TOPIC = "kafka-source";
+    private static final String KAFKA_SINK_TOPIC = "kafka-sink";
+
+    private final Properties configuration = new Properties();
+    private final TopicParameterGroup group = new TopicParameterGroup();
+
+    /**
+     * Constructor.
+     */
+    public TopicEndpointProxyTest() {
+        group.setTopicSinks(new LinkedList<>());
+        group.setTopicSources(new LinkedList<>());
+
+        NoopTopicPropertyBuilder noopSourceBuilder =
+                new NoopTopicPropertyBuilder(MessageBusProperties.PROPERTY_NOOP_SOURCE_TOPICS)
+                        .makeTopic(NOOP_SOURCE_TOPIC);
+        configuration.putAll(noopSourceBuilder.build());
+        group.getTopicSources().add(noopSourceBuilder.getParams());
+
+        NoopTopicPropertyBuilder noopSinkBuilder =
+                new NoopTopicPropertyBuilder(MessageBusProperties.PROPERTY_NOOP_SINK_TOPICS)
+                        .makeTopic(NOOP_SINK_TOPIC);
+        configuration.putAll(noopSinkBuilder.build());
+        group.getTopicSinks().add(noopSinkBuilder.getParams());
+
+        TopicParameters invalidCommInfraParams =
+                new NoopTopicPropertyBuilder(MessageBusProperties.PROPERTY_NOOP_SOURCE_TOPICS)
+                        .makeTopic(NOOP_SOURCE_TOPIC).getParams();
+        invalidCommInfraParams.setTopicCommInfrastructure(Topic.CommInfrastructure.REST.name());
+        group.getTopicSources().add(invalidCommInfraParams);
+        group.getTopicSinks().add(invalidCommInfraParams);
+    }
+
+    private <T extends Topic> boolean exists(List<T> topics, String topicName) {
+        return topics.stream().map(Topic::getTopic).anyMatch(topicName::equals);
+    }
+
+    private <T extends Topic> boolean allSources(List<T> topics) {
+        return exists(topics, NOOP_SOURCE_TOPIC);
+    }
+
+    private <T extends Topic> boolean allSinks(List<T> topics) {
+        return exists(topics, NOOP_SINK_TOPIC);
+    }
+
+    private <T extends Topic> boolean anySource(List<T> topics) {
+        return exists(topics, NOOP_SOURCE_TOPIC);
+    }
+
+    private <T extends Topic> boolean anySink(List<T> topics) {
+        return exists(topics, NOOP_SINK_TOPIC);
+    }
+
+    /**
+     * Destroys all managed topics.
+     */
+    @AfterEach
+    public void tearDown() {
+        NoopTopicFactories.getSinkFactory().destroy();
+        NoopTopicFactories.getSourceFactory().destroy();
+        KafkaTopicFactories.getSinkFactory().destroy();
+        KafkaTopicFactories.getSourceFactory().destroy();
+    }
+
+    @Test
+    void testSerialize() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        manager.addTopicSources(configuration);
+        manager.addTopicSinks(configuration);
+
+        assertThatCode(() -> new GsonTestUtils().compareGson(manager, TopicEndpointProxyTest.class))
+                .doesNotThrowAnyException();
+    }
+
+    @Test
+    void testAddTopicSourcesListOfTopicParameters() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<TopicSource> sources = manager.addTopicSources(group.getTopicSources());
+        assertSame(1, sources.size());
+
+        assertTrue(allSources(sources));
+        assertFalse(anySink(sources));
+
+        sources = manager.addTopicSources(group.getTopicSources());
+        assertSame(1, sources.size());
+        assertTrue(allSources(sources));
+    }
+
+    @Test
+    void testAddTopicSourcesKafka() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        KafkaTopicPropertyBuilder kafkaTopicPropertyBuilder =
+            new KafkaTopicPropertyBuilder(MessageBusProperties.PROPERTY_KAFKA_SOURCE_TOPICS)
+                .makeTopic(KAFKA_SOURCE_TOPIC);
+
+        configuration.putAll(kafkaTopicPropertyBuilder.build());
+        group.getTopicSources().add(kafkaTopicPropertyBuilder.getParams());
+        List<TopicSource> sources = manager.addTopicSources(group.getTopicSources());
+        assertSame(2, sources.size());
+
+        configuration.remove(KAFKA_SOURCE_TOPIC);
+        group.setTopicSources(new LinkedList<>());
+        sources = manager.addTopicSources(group.getTopicSources());
+        assertSame(0, sources.size());
+    }
+
+    @Test
+    void testAddTopicSourcesProperties() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<TopicSource> sources = manager.addTopicSources(configuration);
+        assertSame(1, sources.size());
+
+        assertTrue(allSources(sources));
+        assertFalse(anySink(sources));
+    }
+
+    @Test
+    void testAddTopicSinksListOfTopicParameters() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<TopicSink> sinks = manager.addTopicSinks(group.getTopicSinks());
+        assertSame(1, sinks.size());
+
+        assertFalse(anySource(sinks));
+        assertTrue(allSinks(sinks));
+    }
+
+    @Test
+    void testAddTopicSinksListOfTopicParametersKafka() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<TopicSink> sinks = manager.addTopicSinks(group.getTopicSinks());
+        assertSame(1, sinks.size());
+
+        KafkaTopicPropertyBuilder kafkaTopicPropertyBuilder =
+            new KafkaTopicPropertyBuilder(MessageBusProperties.PROPERTY_KAFKA_SINK_TOPICS)
+                .makeTopic(KAFKA_SINK_TOPIC);
+
+        configuration.putAll(kafkaTopicPropertyBuilder.build());
+        group.getTopicSources().add(kafkaTopicPropertyBuilder.getParams());
+        sinks = manager.addTopicSinks(group.getTopicSources());
+        assertSame(2, sinks.size());
+
+        configuration.remove(KAFKA_SOURCE_TOPIC);
+        group.setTopicSources(new LinkedList<>());
+        sinks = manager.addTopicSinks(group.getTopicSources());
+        assertSame(0, sinks.size());
+    }
+
+    @Test
+    void testAddTopicSinksProperties() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<TopicSink> sinks = manager.addTopicSinks(configuration);
+        assertSame(1, sinks.size());
+
+        assertFalse(anySource(sinks));
+        assertTrue(allSinks(sinks));
+    }
+
+    @Test
+    void testAddTopicsProperties() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<Topic> topics = manager.addTopics(configuration);
+        assertSame(2, topics.size());
+
+        assertTrue(allSources(topics));
+        assertTrue(allSinks(topics));
+    }
+
+    @Test
+    void testAddTopicsTopicParameterGroup() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<Topic> topics = manager.addTopics(group);
+        assertSame(2, topics.size());
+
+        assertTrue(allSources(topics));
+        assertTrue(allSinks(topics));
+    }
+
+    @Test
+    void testAddTopicsTopicParameterGroupNull() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        List<Topic> topics = manager.addTopics(new TopicParameterGroup());
+        assertEquals(0, topics.size());
+    }
+
+    @Test
+    void testLockSinks_lockSources_locked() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+        manager.lock();
+        for (Topic topic : manager.addTopics(group)) {
+            assertTrue(topic.isLocked());
+        }
+    }
+
+    @Test
+    void testLockSinks_lockSources_unlocked() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+        for (Topic topic : manager.addTopics(group)) {
+            assertFalse(topic.isLocked());
+        }
+    }
+
+    @Test
+    void testGetTopicSources() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        manager.addTopicSources(configuration);
+        manager.addTopicSinks(configuration);
+
+        List<TopicSource> sources = manager.getTopicSources();
+        assertSame(1, sources.size());
+
+        assertTrue(allSources(sources));
+        assertFalse(anySink(sources));
+
+        assertThatThrownBy(() -> manager.getKafkaTopicSource("testTopic"))
+            .hasMessageContaining("KafkaTopiceSource for testTopic not found");
+
+        List<String> topicName = null;
+        assertThatThrownBy(() -> manager.getTopicSources(topicName))
+            .hasMessageContaining("must provide a list of topics");
+    }
+
+    @Test
+    void testGetTopicSinks() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        manager.addTopicSources(configuration);
+        manager.addTopicSinks(configuration);
+
+        List<TopicSink> sinks = manager.getTopicSinks();
+        assertSame(1, sinks.size());
+
+        assertFalse(anySource(sinks));
+        assertTrue(allSinks(sinks));
+
+        final List<String> sinks2 = null;
+        assertThatThrownBy(() -> manager.getTopicSinks(sinks2)).hasMessageContaining("must provide a list of topics");
+
+        List<String> sinks3 = List.of(NOOP_SINK_TOPIC);
+        assertThatCode(() -> manager.getTopicSinks(sinks3)).doesNotThrowAnyException();
+
+        String sinkTest = null;
+        assertThatThrownBy(() -> manager.getTopicSinks(sinkTest))
+            .isInstanceOf(IllegalArgumentException.class)
+            .hasMessageContaining("Invalid parameter");
+
+        assertThatThrownBy(() -> manager.getKafkaTopicSink("testTopic"))
+            .hasMessageContaining("KafkaTopicSink for testTopic not found");
+    }
+
+    @Test
+    void testGetNoopTopicSources() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        manager.addTopicSources(configuration);
+        assertSame(1, manager.getNoopTopicSources().size());
+    }
+
+    @Test
+    void testGetNoopTopicSinks() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        manager.addTopicSinks(configuration);
+        assertSame(1, manager.getNoopTopicSinks().size());
+    }
+
+    @Test
+    void testLifecycle() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        assertTrue(manager.start());
+        assertTrue(manager.isAlive());
+
+        assertTrue(manager.stop());
+        assertFalse(manager.isAlive());
+
+        assertTrue(manager.start());
+        assertTrue(manager.isAlive());
+
+        manager.shutdown();
+        assertFalse(manager.isAlive());
+    }
+
+    @Test
+    void testLock() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+
+        manager.lock();
+        assertTrue(manager.isLocked());
+
+        manager.unlock();
+        assertFalse(manager.isLocked());
+    }
+
+    @Test
+    void testGetTopicSource() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+        manager.addTopicSources(configuration);
+
+        assertSame(NOOP_SOURCE_TOPIC, manager.getTopicSource(CommInfrastructure.NOOP, NOOP_SOURCE_TOPIC).getTopic());
+
+        assertThatIllegalStateException()
+                .isThrownBy(() -> manager.getTopicSource(CommInfrastructure.NOOP, NOOP_SINK_TOPIC));
+    }
+
+    @Test
+    void testGetTopicSink() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+        manager.addTopicSinks(configuration);
+
+        assertSame(NOOP_SINK_TOPIC, manager.getTopicSink(CommInfrastructure.NOOP, NOOP_SINK_TOPIC).getTopic());
+
+        assertThatIllegalStateException()
+                .isThrownBy(() -> manager.getTopicSink(CommInfrastructure.NOOP, NOOP_SOURCE_TOPIC));
+    }
+
+    @Test
+    void testGetNoopTopicSource() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+        manager.addTopicSources(configuration);
+
+        assertSame(NOOP_SOURCE_TOPIC, manager.getNoopTopicSource(NOOP_SOURCE_TOPIC).getTopic());
+
+        assertThatIllegalArgumentException().isThrownBy(() -> manager.getNoopTopicSource(null));
+        assertThatIllegalArgumentException().isThrownBy(() -> manager.getNoopTopicSource(""));
+    }
+
+    @Test
+    void testGetNoopTopicSink() {
+        TopicEndpoint manager = new TopicEndpointProxy();
+        manager.addTopicSinks(configuration);
+
+        assertSame(NOOP_SINK_TOPIC, manager.getNoopTopicSink(NOOP_SINK_TOPIC).getTopic());
+
+        assertThatIllegalArgumentException().isThrownBy(() -> manager.getNoopTopicSink(null));
+        assertThatIllegalArgumentException().isThrownBy(() -> manager.getNoopTopicSink(""));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/TopicParameterGroupTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/TopicParameterGroupTest.java
new file mode 100644
index 00000000..db28892e
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/TopicParameterGroupTest.java
@@ -0,0 +1,147 @@
+/*-
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2019-2024 Nordix Foundation.
+ *  Modifications Copyright (C) 2019, 2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.beans.PropertyDescriptor;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.List;
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.parameters.ValidationResult;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.parameters.topic.TopicParameterGroup;
+import org.onap.policy.common.parameters.topic.TopicParameters;
+import org.onap.policy.common.utils.coder.Coder;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
+
+/**
+ * Class to perform unit test of {@link TopicParameterGroup}.
+ *
+ * @author Ajith Sreekumar (ajith.sreekumar@est.tech)
+ */
+class TopicParameterGroupTest {
+    private static final CommonTestData testData = new CommonTestData();
+    private static final Coder coder = new StandardCoder();
+    private final String packageDir = "src/test/resources/org/onap/policy/common/message/bus/parameters/";
+
+    @Test
+    void test() throws CoderException {
+        final TopicParameterGroup topicParameterGroup =
+                testData.toObject(testData.getTopicParameterGroupMap(false), TopicParameterGroup.class);
+        final ValidationResult validationResult = topicParameterGroup.validate();
+        assertTrue(validationResult.isValid());
+        assertEquals(CommonTestData.TOPIC_PARAMS, topicParameterGroup.getTopicSinks());
+        assertEquals(CommonTestData.TOPIC_PARAMS, topicParameterGroup.getTopicSources());
+
+        // these should default to true
+        assertTrue(new TopicParameters().isManaged());
+        assertTrue(coder.decode("{}", TopicParameters.class).isManaged());
+
+        // but can be overridden
+        assertFalse(coder.decode("{'managed':false}".replace('\'', '"'), TopicParameters.class).isManaged());
+    }
+
+    @Test
+    void testValidate() {
+        final TopicParameterGroup topicParameterGroup =
+            testData.toObject(testData.getTopicParameterGroupMap(false), TopicParameterGroup.class);
+        final ValidationResult result = topicParameterGroup.validate();
+        assertNull(result.getResult());
+        assertTrue(result.isValid());
+    }
+
+    @Test
+    void test_valid() throws Exception {
+        String json = testData.getParameterGroupAsString(
+            packageDir + "TopicParameters_valid.json");
+        TopicParameterGroup topicParameterGroup = coder.decode(json, TopicParameterGroup.class);
+        final ValidationResult result = topicParameterGroup.validate();
+        assertNull(result.getResult());
+        assertTrue(result.isValid());
+    }
+
+    @Test
+    void test_invalid() throws Exception {
+        String json = testData.getParameterGroupAsString(
+            packageDir + "TopicParameters_invalid.json");
+        TopicParameterGroup topicParameterGroup = coder.decode(json, TopicParameterGroup.class);
+        final ValidationResult result = topicParameterGroup.validate();
+        assertFalse(result.isValid());
+        assertTrue(result.getResult().contains("INVALID"));
+    }
+
+    @Test
+    void test_missing_mandatory_params() throws Exception {
+        String json = testData.getParameterGroupAsString(
+            packageDir + "TopicParameters_missing_mandatory.json");
+        TopicParameterGroup topicParameterGroup = coder.decode(json, TopicParameterGroup.class);
+        final ValidationResult result = topicParameterGroup.validate();
+        assertTrue(result.getResult().contains("Mandatory parameters are missing"));
+        assertFalse(result.isValid());
+    }
+
+    @Test
+    void test_allParams() throws Exception {
+        String json = testData.getParameterGroupAsString(
+            packageDir + "TopicParameters_all_params.json");
+        TopicParameterGroup topicParameterGroup = coder.decode(json, TopicParameterGroup.class);
+        final ValidationResult result = topicParameterGroup.validate();
+        assertNull(result.getResult());
+        assertTrue(result.isValid());
+        assertTrue(checkIfAllParamsNotEmpty(topicParameterGroup.getTopicSinks()));
+        assertTrue(checkIfAllParamsNotEmpty(topicParameterGroup.getTopicSources()));
+    }
+
+    /**
+     * Method to check if all parameters in TopicParameters are set.
+     * Any parameters added to @link TopicParameters or @link BusTopicParams must be added to
+     * TopicParameters_all_params.json.
+     *
+     * @param topicParametersList list of topic parameters
+     * @return true if all parameters are not empty (if string) or true (if boolean)
+     * @throws Exception the exception
+     */
+    private boolean checkIfAllParamsNotEmpty(List<TopicParameters> topicParametersList) throws Exception {
+        for (TopicParameters topicParameters : topicParametersList) {
+            Field[] fields = BusTopicParams.class.getDeclaredFields();
+            for (Field field : fields) {
+                if (!field.isSynthetic() && !Modifier.isStatic(field.getModifiers())) {
+                    Object parameter = new PropertyDescriptor(field.getName(), TopicParameters.class).getReadMethod()
+                        .invoke(topicParameters);
+                    if ((parameter instanceof String && StringUtils.isBlank(parameter.toString()))
+                        || (parameter instanceof Boolean && !(Boolean) parameter)
+                        || (parameter instanceof Number && ((Number) parameter).longValue() == 0)) {
+                        return false;
+                    }
+                }
+            }
+        }
+        return true;
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusConsumerTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusConsumerTest.java
new file mode 100644
index 00000000..207023e5
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusConsumerTest.java
@@ -0,0 +1,282 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2023-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.concurrent.CountDownLatch;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.apache.kafka.clients.consumer.ConsumerRecords;
+import org.apache.kafka.clients.consumer.KafkaConsumer;
+import org.apache.kafka.common.TopicPartition;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.onap.policy.common.message.bus.event.base.BusConsumer.FetchingBusConsumer;
+import org.onap.policy.common.message.bus.event.base.BusConsumer.KafkaConsumerWrapper;
+import org.onap.policy.common.message.bus.properties.MessageBusProperties;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+class BusConsumerTest extends TopicTestBase {
+
+    private static final int SHORT_TIMEOUT_MILLIS = 10;
+    private static final int LONG_TIMEOUT_MILLIS = 3000;
+
+    @Mock
+    KafkaConsumer<String, String> mockedKafkaConsumer;
+
+    AutoCloseable closeable;
+
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+        closeable = MockitoAnnotations.openMocks(this);
+    }
+
+    @AfterEach
+    public void tearDown() throws Exception {
+        closeable.close();
+    }
+
+
+    @Test
+    void testFetchingBusConsumer() {
+        // should not be negative
+        var cons = new FetchingBusConsumerImpl(makeBuilder().fetchTimeout(-1).build());
+        assertThat(cons.getSleepTime()).isEqualTo(MessageBusProperties.DEFAULT_TIMEOUT_MS_FETCH);
+
+        // should not be zero
+        cons = new FetchingBusConsumerImpl(makeBuilder().fetchTimeout(0).build());
+        assertThat(cons.getSleepTime()).isEqualTo(MessageBusProperties.DEFAULT_TIMEOUT_MS_FETCH);
+
+        // should not be too large
+        cons = new FetchingBusConsumerImpl(
+                        makeBuilder().fetchTimeout(MessageBusProperties.DEFAULT_TIMEOUT_MS_FETCH + 100).build());
+        assertThat(cons.getSleepTime()).isEqualTo(MessageBusProperties.DEFAULT_TIMEOUT_MS_FETCH);
+
+        // should not be what was specified
+        cons = new FetchingBusConsumerImpl(makeBuilder().fetchTimeout(100).build());
+        assertThat(cons.getSleepTime()).isEqualTo(100);
+    }
+
+    @Test
+    void testFetchingBusConsumerSleepAfterFetchFailure() throws InterruptedException {
+
+        var cons = new FetchingBusConsumerImpl(makeBuilder().fetchTimeout(SHORT_TIMEOUT_MILLIS).build()) {
+
+            private CountDownLatch started = new CountDownLatch(1);
+
+            @Override
+            protected void sleepAfterFetchFailure() {
+                started.countDown();
+                super.sleepAfterFetchFailure();
+            }
+        };
+
+        // full sleep
+        long tstart = System.currentTimeMillis();
+        cons.sleepAfterFetchFailure();
+        assertThat(System.currentTimeMillis() - tstart).isGreaterThanOrEqualTo(SHORT_TIMEOUT_MILLIS);
+
+        // close while sleeping - sleep should halt prematurely
+        cons.fetchTimeout = LONG_TIMEOUT_MILLIS;
+        cons.started = new CountDownLatch(1);
+        Thread thread = new Thread(cons::sleepAfterFetchFailure);
+        tstart = System.currentTimeMillis();
+        thread.start();
+        cons.started.await();
+        cons.close();
+        thread.join();
+        assertThat(System.currentTimeMillis() - tstart).isLessThan(LONG_TIMEOUT_MILLIS);
+
+        // interrupt while sleeping - sleep should halt prematurely
+        cons.fetchTimeout = LONG_TIMEOUT_MILLIS;
+        cons.started = new CountDownLatch(1);
+        thread = new Thread(cons::sleepAfterFetchFailure);
+        tstart = System.currentTimeMillis();
+        thread.start();
+        cons.started.await();
+        thread.interrupt();
+        thread.join();
+        assertThat(System.currentTimeMillis() - tstart).isLessThan(LONG_TIMEOUT_MILLIS);
+    }
+
+    @Test
+    void testKafkaConsumerWrapper() {
+        // verify that different wrappers can be built
+        assertThatCode(() -> new KafkaConsumerWrapper(makeKafkaBuilder().build())).doesNotThrowAnyException();
+    }
+
+    @Test
+    void testKafkaConsumerWrapper_InvalidTopic() {
+        BusTopicParams params = makeBuilder().topic(null).build();
+        assertThatThrownBy(() -> new KafkaConsumerWrapper(params))
+            .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testKafkaConsumerWrapperFetch() {
+
+        //Setup Properties for consumer
+        Properties kafkaProps = new Properties();
+        kafkaProps.setProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
+        kafkaProps.setProperty(ConsumerConfig.GROUP_ID_CONFIG, "test");
+        kafkaProps.setProperty("enable.auto.commit", "true");
+        kafkaProps.setProperty("auto.commit.interval.ms", "1000");
+        kafkaProps.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
+            "org.apache.kafka.common.serialization.StringDeserializer");
+        kafkaProps.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
+            "org.apache.kafka.common.serialization.StringDeserializer");
+        kafkaProps.setProperty(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+        kafkaProps.setProperty(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "false");
+
+        KafkaConsumerWrapper kafka = new KafkaConsumerWrapper(makeKafkaBuilder().build());
+        KafkaConsumer<String, String> consumer = new KafkaConsumer<>(kafkaProps);
+        kafka.consumer = consumer;
+
+        assertThrows(java.lang.IllegalStateException.class, () -> kafka.fetch().iterator().hasNext());
+        consumer.close();
+    }
+
+    @Test
+    void testFetchNoMessages() {
+        KafkaConsumerWrapper kafkaConsumerWrapper = new KafkaConsumerWrapper(makeKafkaBuilder().build());
+        kafkaConsumerWrapper.consumer = mockedKafkaConsumer;
+
+        when(mockedKafkaConsumer.poll(any())).thenReturn(new ConsumerRecords<>(Collections.emptyMap()));
+
+        Iterable<String> result = kafkaConsumerWrapper.fetch();
+
+        verify(mockedKafkaConsumer).poll(any());
+
+        assertNotNull(result);
+
+        assertFalse(result.iterator().hasNext());
+
+        mockedKafkaConsumer.close();
+    }
+
+    @Test
+    void testFetchWithMessages() {
+        // Setup
+        KafkaConsumerWrapper kafkaConsumerWrapper = new KafkaConsumerWrapper(makeKafkaBuilder().build());
+        kafkaConsumerWrapper.consumer = mockedKafkaConsumer;
+
+        ConsumerRecord<String, String> customerRecord =
+            new ConsumerRecord<>("my-effective-topic", 0, 0, "key", "value");
+        Map<TopicPartition, List<ConsumerRecord<String, String>>> recordsMap = new HashMap<>();
+        recordsMap.put(new TopicPartition("my-effective-topic", 0), Collections.singletonList(customerRecord));
+        ConsumerRecords<String, String> consumerRecords = new ConsumerRecords<>(recordsMap);
+
+        when(mockedKafkaConsumer.poll(any())).thenReturn(consumerRecords);
+
+        Iterable<String> result = kafkaConsumerWrapper.fetch();
+
+        verify(mockedKafkaConsumer, times(1)).poll(any());
+
+        verify(mockedKafkaConsumer, times(1)).commitSync(any(Map.class));
+
+        assertNotNull(result);
+
+        assertTrue(result.iterator().hasNext());
+
+        assertEquals("value", result.iterator().next());
+
+        mockedKafkaConsumer.close();
+    }
+
+    @Test
+    void testFetchWithMessagesAndTraceParent() {
+        // Setup
+        KafkaConsumerWrapper kafkaConsumerWrapper = new KafkaConsumerWrapper(makeKafkaBuilder().build());
+        kafkaConsumerWrapper.consumer = mockedKafkaConsumer;
+
+        ConsumerRecord<String, String> customerRecord =
+            new ConsumerRecord<>("my-effective-topic", 0, 0, "key", "value");
+        customerRecord.headers().add(
+                "traceparent",
+                "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01".getBytes(StandardCharsets.UTF_8)
+        );
+
+        Map<TopicPartition, List<ConsumerRecord<String, String>>> recordsMap = new HashMap<>();
+        recordsMap.put(new TopicPartition("my-effective-topic", 0), Collections.singletonList(customerRecord));
+        ConsumerRecords<String, String> consumerRecords = new ConsumerRecords<>(recordsMap);
+
+        when(mockedKafkaConsumer.poll(any())).thenReturn(consumerRecords);
+
+        Iterable<String> result = kafkaConsumerWrapper.fetch();
+
+        verify(mockedKafkaConsumer, times(1)).poll(any());
+
+        verify(mockedKafkaConsumer, times(1)).commitSync(any(Map.class));
+
+        assertNotNull(result);
+
+        assertTrue(result.iterator().hasNext());
+
+        assertEquals("value", result.iterator().next());
+
+        mockedKafkaConsumer.close();
+    }
+
+
+    @Test
+    void testKafkaConsumerWrapperClose() {
+        assertThatCode(() -> new KafkaConsumerWrapper(makeKafkaBuilder().build()).close()).doesNotThrowAnyException();
+    }
+
+    @Test
+    void testKafkaConsumerWrapperToString() {
+        assertNotNull(new KafkaConsumerWrapper(makeKafkaBuilder().build()) {}.toString());
+    }
+
+    private static class FetchingBusConsumerImpl extends FetchingBusConsumer {
+
+        protected FetchingBusConsumerImpl(BusTopicParams busTopicParams) {
+            super(busTopicParams);
+        }
+
+        @Override
+        public Iterable<String> fetch() {
+            return null;
+        }
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusTopicBaseTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusTopicBaseTest.java
new file mode 100644
index 00000000..343a56a8
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusTopicBaseTest.java
@@ -0,0 +1,139 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.utils.gson.GsonTestUtils;
+
+class BusTopicBaseTest extends TopicTestBase {
+
+    private BusTopicBaseImpl base;
+
+    /**
+     * Initializes the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        base = new BusTopicBaseImpl(builder.build());
+    }
+
+    @Test
+    void testToString() {
+        assertNotNull(base.toString());
+    }
+
+    @Test
+    void testSerialize() {
+        assertThatCode(() -> new GsonTestUtils().compareGson(base, BusTopicBaseTest.class)).doesNotThrowAnyException();
+    }
+
+    @Test
+    void testGetApiKey() {
+        assertEquals(MY_API_KEY, base.getApiKey());
+    }
+
+    @Test
+    void testGetApiSecret() {
+        assertEquals(MY_API_SECRET, base.getApiSecret());
+    }
+
+    @Test
+    void testIsUseHttps() {
+        assertTrue(base.isUseHttps());
+        assertFalse(new BusTopicBaseImpl(builder.useHttps(false).build()).isUseHttps());
+    }
+
+    @Test
+    void testIsAllowSelfSignedCerts() {
+        assertTrue(base.isAllowSelfSignedCerts());
+        assertFalse(new BusTopicBaseImpl(builder.allowSelfSignedCerts(false).build()).isAllowSelfSignedCerts());
+    }
+
+    @Test
+    void testTopic() {
+        assertEquals(MY_TOPIC, base.getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, base.getEffectiveTopic());
+        assertNotEquals(base.getTopic(), base.getEffectiveTopic());
+    }
+
+    @Test
+    void testAnyNullOrEmpty() {
+        assertFalse(base.anyNullOrEmpty());
+        assertFalse(base.anyNullOrEmpty("any-none-null", "any-none-null-B"));
+
+        assertTrue(base.anyNullOrEmpty(null, "any-first-null"));
+        assertTrue(base.anyNullOrEmpty("any-middle-null", null, "any-middle-null-B"));
+        assertTrue(base.anyNullOrEmpty("any-last-null", null));
+        assertTrue(base.anyNullOrEmpty("any-empty", ""));
+    }
+
+    @Test
+    void testAllNullOrEmpty() {
+        assertTrue(base.allNullOrEmpty());
+        assertTrue(base.allNullOrEmpty(""));
+        assertTrue(base.allNullOrEmpty(null, ""));
+
+        assertFalse(base.allNullOrEmpty("all-ok-only-one"));
+        assertFalse(base.allNullOrEmpty("all-ok-one", "all-ok-two"));
+        assertFalse(base.allNullOrEmpty("all-ok-null", null));
+        assertFalse(base.allNullOrEmpty("", "all-ok-empty"));
+        assertFalse(base.allNullOrEmpty("", "all-one-ok", null));
+    }
+
+    private static class BusTopicBaseImpl extends BusTopicBase {
+
+        public BusTopicBaseImpl(BusTopicParams busTopicParams) {
+            super(busTopicParams);
+        }
+
+        @Override
+        public CommInfrastructure getTopicCommInfrastructure() {
+            return CommInfrastructure.NOOP;
+        }
+
+        @Override
+        public boolean start() {
+            return true;
+        }
+
+        @Override
+        public boolean stop() {
+            return true;
+        }
+
+        @Override
+        public void shutdown() {
+            // do nothing
+        }
+
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusTopicFactoryTestBase.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusTopicFactoryTestBase.java
new file mode 100644
index 00000000..bd531114
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/BusTopicFactoryTestBase.java
@@ -0,0 +1,238 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_ALLOW_SELF_SIGNED_CERTIFICATES_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_HTTP_HTTPS_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_MANAGED_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX;
+
+import java.util.List;
+import java.util.Properties;
+import java.util.function.Predicate;
+import org.onap.policy.common.message.bus.event.Topic;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+/**
+ * Base class for Topic Factory tests that use BusTopicParams.
+ *
+ * @param <T> type of topic managed by the factory
+ */
+public abstract class BusTopicFactoryTestBase<T extends Topic> extends TopicFactoryTestBase<T> {
+
+    /**
+     * Builds a topic.
+     *
+     * @param params the parameters used to configure the topic
+     * @return a new topic
+     */
+    protected abstract T buildTopic(BusTopicParams params);
+
+    /**
+     * Builds a topic.
+     *
+     * @param servers list of servers
+     * @param topic the topic name
+     * @return a new topic
+     */
+    protected abstract T buildTopic(List<String> servers, String topic);
+
+    /**
+     * Gets the parameters used to build the most recent topic.
+     *
+     * @return the most recent topic's parameters
+     */
+    protected abstract BusTopicParams getLastParams();
+
+    /**
+     * Tests building a topic using BusTopicParams.
+     */
+    public void testBuildBusTopicParams() {
+        initFactory();
+
+        // two unmanaged topics
+        T item = buildTopic(makeBuilder().managed(false).effectiveTopic(null).build());
+        T item2 = buildTopic(makeBuilder().managed(false).topic(TOPIC2).build());
+        assertNotNull(item);
+        assertNotNull(item2);
+        assertEquals(item.getTopic(), item.getEffectiveTopic());
+        assertNotEquals(item2.getTopic(), item2.getEffectiveTopic());
+        assertNotSame(item, item2);
+
+        // duplicate topics, but since they aren't managed, they should be different
+        T item3 = buildTopic(makeBuilder().managed(false).build());
+        T item4 = buildTopic(makeBuilder().managed(false).effectiveTopic(TOPIC2).build());
+        assertNotNull(item3);
+        assertNotNull(item4);
+        assertEquals(MY_TOPIC, item4.getTopic());
+        assertEquals(TOPIC2, item4.getEffectiveTopic());
+        assertNotSame(item, item3);
+        assertNotSame(item, item4);
+        assertNotSame(item3, item4);
+
+        // two managed topics
+        T item5 = buildTopic(makeBuilder().build());
+        T item6 = buildTopic(makeBuilder().topic(TOPIC2).build());
+        assertNotNull(item5);
+        assertNotNull(item6);
+
+        // re-build same managed topics - should get exact same objects
+        assertSame(item5, buildTopic(makeBuilder().topic(MY_TOPIC).build()));
+        assertSame(item6, buildTopic(makeBuilder().topic(TOPIC2).build()));
+    }
+
+    /**
+     * Tests exception cases when building a topic using BusTopicParams.
+     */
+    public void testBuildBusTopicParams_Ex() {
+        // null topic
+        assertThatIllegalArgumentException().isThrownBy(() -> buildTopic(makeBuilder().topic(null).build()));
+
+        // empty topic
+        assertThatIllegalArgumentException().isThrownBy(() -> buildTopic(makeBuilder().topic("").build()));
+    }
+
+    /**
+     * Tests building a topic using a list of servers and a topic.
+     */
+    public void testBuildListOfStringString() {
+        initFactory();
+
+        T item1 = buildTopic(servers, MY_TOPIC);
+        assertNotNull(item1);
+
+        // check parameters that were used
+        BusTopicParams params = getLastParams();
+        assertEquals(servers, params.getServers());
+        assertEquals(MY_TOPIC, params.getTopic());
+        assertTrue(params.isManaged());
+        assertFalse(params.isUseHttps());
+
+        T item2 = buildTopic(servers, TOPIC2);
+        assertNotNull(item2);
+        assertNotSame(item1, item2);
+
+        // duplicate - should be the same, as these topics are managed
+        T item3 = buildTopic(servers, TOPIC2);
+        assertSame(item2, item3);
+    }
+
+    /**
+     * Tests building a topic using Properties. Verifies parameters specific to Bus
+     * topics.
+     */
+    public void testBuildProperties() {
+        initFactory();
+
+        List<T> topics = buildTopics(makePropBuilder().makeTopic(MY_TOPIC).build());
+        assertEquals(1, topics.size());
+        assertEquals(MY_TOPIC, topics.get(0).getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, topics.get(0).getEffectiveTopic());
+
+        BusTopicParams params = getLastParams();
+        assertTrue(params.isManaged());
+        assertTrue(params.isUseHttps());
+        assertTrue(params.isAllowSelfSignedCerts());
+        assertEquals(MY_API_KEY, params.getApiKey());
+        assertEquals(MY_API_SECRET, params.getApiSecret());
+        assertEquals(List.of(SERVER), params.getServers());
+        assertEquals(MY_TOPIC, params.getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, params.getEffectiveTopic());
+
+        List<T> topics2 = buildTopics(makePropBuilder().makeTopic(TOPIC3)
+            .removeTopicProperty(PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX).build());
+        assertEquals(1, topics2.size());
+        assertEquals(TOPIC3, topics2.get(0).getTopic());
+        assertEquals(topics2.get(0).getTopic(), topics2.get(0).getEffectiveTopic());
+    }
+
+    @Override
+    void testBuildProperties_Variations() {
+        super.testBuildProperties_Variations();
+
+        // check boolean properties that default to true
+        checkDefault(PROPERTY_MANAGED_SUFFIX, BusTopicParams::isManaged);
+
+        // check boolean properties that default to false
+        checkDefault(PROPERTY_HTTP_HTTPS_SUFFIX, params -> !params.isUseHttps());
+        checkDefault(PROPERTY_ALLOW_SELF_SIGNED_CERTIFICATES_SUFFIX, params -> !params.isAllowSelfSignedCerts());
+    }
+
+    /**
+     * Verifies that a parameter has the correct default, if the original builder property
+     * is not provided.
+     *
+     * @param builderName name of the builder property
+     * @param validate function to test the validity of the property
+     * @param values the values to which the property should be set, defaults to
+     *        {@code null} and ""
+     */
+    protected void checkDefault(String builderName, Predicate<BusTopicParams> validate, Object... values) {
+        Object[] values2 = (values.length > 0 ? values : new Object[] {null, ""});
+
+        for (Object value : values2) {
+            // always start with a fresh factory
+            initFactory();
+
+            TopicPropertyBuilder builder = makePropBuilder().makeTopic(MY_TOPIC);
+
+            if (value == null) {
+                builder.removeTopicProperty(builderName);
+
+            } else {
+                builder.setTopicProperty(builderName, value.toString());
+            }
+
+            assertEquals(1, buildTopics(builder.build()).size(), "size for default " + value);
+            assertTrue(validate.test(getLastParams()), "default for " + value);
+        }
+    }
+
+    /**
+     * Verifies that an "additional" property does not exist, if the original builder
+     * property is not provided.
+     *
+     * @param builderName name of the builder property
+     * @param addName name of the "additional" property
+     */
+    public void expectNullAddProp(String builderName, String addName) {
+
+        // remove the property
+        initFactory();
+        Properties props = makePropBuilder().makeTopic(MY_TOPIC).removeTopicProperty(builderName).build();
+        assertEquals(1, buildTopics(props).size());
+        assertFalse(getLastParams().getAdditionalProps().containsKey(addName));
+
+
+        // repeat, this time using an empty string instead of null
+        initFactory();
+        props = makePropBuilder().makeTopic(MY_TOPIC).setTopicProperty(builderName, "").build();
+        assertEquals(1, buildTopics(props).size());
+        assertFalse(getLastParams().getAdditionalProps().containsKey(addName));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/InlineBusTopicSinkTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/InlineBusTopicSinkTest.java
new file mode 100644
index 00000000..820fc2c3
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/InlineBusTopicSinkTest.java
@@ -0,0 +1,230 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.utils.gson.GsonTestUtils;
+
+class InlineBusTopicSinkTest extends TopicTestBase {
+
+    private InlineBusTopicSinkImpl sink;
+
+    /**
+     * Creates the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        sink = new InlineBusTopicSinkImpl(makeBuilder().build());
+    }
+
+    @AfterEach
+    public void tearDown() {
+        sink.shutdown();
+    }
+
+    @Test
+    void testSerialize() {
+        assertThatCode(() -> new GsonTestUtils().compareGson(sink, InlineBusTopicSinkTest.class))
+                        .doesNotThrowAnyException();
+    }
+
+    @Test
+    void testInlineBusTopicSinkImpl() {
+        // verify that different wrappers can be built
+        sink = new InlineBusTopicSinkImpl(makeBuilder().build());
+        assertEquals(MY_PARTITION, sink.getPartitionKey());
+
+        sink = new InlineBusTopicSinkImpl(makeBuilder().partitionId(null).build());
+        assertNotNull(sink.getPartitionKey());
+    }
+
+    @Test
+    void testStart() {
+        assertTrue(sink.start());
+        assertEquals(1, sink.initCount);
+
+        // re-start, init() should not be invoked again
+        assertTrue(sink.start());
+        assertEquals(1, sink.initCount);
+    }
+
+    @Test
+    void testStart_Locked() {
+        sink.lock();
+        assertThatThrownBy(() -> sink.start()).isInstanceOf(IllegalStateException.class);
+    }
+
+    @Test
+    void testStop() {
+        BusPublisher pub = mock(BusPublisher.class);
+        sink.publisher = pub;
+
+        assertTrue(sink.stop());
+        verify(pub).close();
+
+        // stop again, shouldn't not invoke close() again
+        assertFalse(sink.stop());
+        verify(pub).close();
+
+        // publisher throws exception
+        sink = new InlineBusTopicSinkImpl(makeBuilder().build());
+        sink.publisher = pub;
+        doThrow(new RuntimeException(EXPECTED)).when(pub).close();
+        assertTrue(sink.stop());
+    }
+
+    @Test
+    void testSend() {
+        sink.start();
+        BusPublisher pub = mock(BusPublisher.class);
+        sink.publisher = pub;
+
+        TopicListener listener = mock(TopicListener.class);
+        sink.register(listener);
+
+        assertTrue(sink.send(MY_MESSAGE));
+
+        verify(pub).send(MY_PARTITION, MY_MESSAGE);
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE);
+        assertEquals(List.of(MY_MESSAGE), Arrays.asList(sink.getRecentEvents()));
+
+        // arrange for send to throw an exception
+        when(pub.send(anyString(), anyString())).thenThrow(new RuntimeException(EXPECTED));
+
+        assertFalse(sink.send(MY_MESSAGE));
+
+        // no more event deliveries
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE);
+    }
+
+    @Test
+    void testSend_NullMessage() {
+        sink.start();
+        sink.publisher = mock(BusPublisher.class);
+
+        assertThatThrownBy(() -> sink.send(null)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testSend_EmptyMessage() {
+        sink.start();
+        sink.publisher = mock(BusPublisher.class);
+
+        assertThatThrownBy(() -> sink.send("")).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testSend_NotStarted() {
+        sink.publisher = mock(BusPublisher.class);
+        assertThatThrownBy(() -> sink.send(MY_MESSAGE)).isInstanceOf(IllegalStateException.class);
+    }
+
+    @Test
+    void testSetPartitionKey_getPartitionKey() {
+        assertEquals(MY_PARTITION, sink.getPartitionKey());
+
+        sink.setPartitionKey("part-B");
+        assertEquals("part-B", sink.getPartitionKey());
+    }
+
+    @Test
+    void testShutdown() {
+        BusPublisher pub = mock(BusPublisher.class);
+        sink.publisher = pub;
+
+        sink.shutdown();
+        verify(pub).close();
+    }
+
+    @Test
+    void testAnyNullOrEmpty() {
+        assertFalse(sink.anyNullOrEmpty());
+        assertFalse(sink.anyNullOrEmpty("any-none-null", "any-none-null-B"));
+
+        assertTrue(sink.anyNullOrEmpty(null, "any-first-null"));
+        assertTrue(sink.anyNullOrEmpty("any-middle-null", null, "any-middle-null-B"));
+        assertTrue(sink.anyNullOrEmpty("any-last-null", null));
+        assertTrue(sink.anyNullOrEmpty("any-empty", ""));
+    }
+
+    @Test
+    void testAllNullOrEmpty() {
+        assertTrue(sink.allNullOrEmpty());
+        assertTrue(sink.allNullOrEmpty(""));
+        assertTrue(sink.allNullOrEmpty(null, ""));
+
+        assertFalse(sink.allNullOrEmpty("all-ok-only-one"));
+        assertFalse(sink.allNullOrEmpty("all-ok-one", "all-ok-two"));
+        assertFalse(sink.allNullOrEmpty("all-ok-null", null));
+        assertFalse(sink.allNullOrEmpty("", "all-ok-empty"));
+        assertFalse(sink.allNullOrEmpty("", "all-one-ok", null));
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(sink.toString().startsWith("InlineBusTopicSink ["));
+    }
+
+    /**
+     * Implementation of InlineBusTopicSink that tracks the number of times that init() is
+     * invoked.
+     */
+    private static class InlineBusTopicSinkImpl extends InlineBusTopicSink {
+
+        private int initCount = 0;
+
+        public InlineBusTopicSinkImpl(BusTopicParams busTopicParams) {
+            super(busTopicParams);
+        }
+
+        @Override
+        public CommInfrastructure getTopicCommInfrastructure() {
+            return CommInfrastructure.NOOP;
+        }
+
+        @Override
+        public void init() {
+            ++initCount;
+        }
+
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSourceTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSourceTest.java
new file mode 100644
index 00000000..8ad8e8fd
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSourceTest.java
@@ -0,0 +1,375 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.util.Arrays;
+import java.util.Collections;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.utils.gson.GsonTestUtils;
+import org.onap.policy.common.utils.network.NetworkUtil;
+
+class SingleThreadedBusTopicSourceTest extends TopicTestBase {
+    private Thread thread;
+    private BusConsumer cons;
+    private TopicListener listener;
+    private SingleThreadedBusTopicSourceImpl source;
+
+    /**
+     * Creates the object to be tested, as well as various mocks.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        thread = mock(Thread.class);
+        cons = mock(BusConsumer.class);
+        listener = mock(TopicListener.class);
+        source = new SingleThreadedBusTopicSourceImpl(makeBuilder().build());
+    }
+
+    @AfterEach
+    public void tearDown() {
+        source.shutdown();
+    }
+
+    @Test
+    void testSerialize() {
+        assertThatCode(() -> new GsonTestUtils().compareGson(source, SingleThreadedBusTopicSourceTest.class))
+                        .doesNotThrowAnyException();
+    }
+
+    @Test
+    void testRegister() {
+        source.register(listener);
+        assertEquals(1, source.initCount);
+        source.offer(MY_MESSAGE);
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE);
+
+        // register another - should not re-init
+        TopicListener listener2 = mock(TopicListener.class);
+        source.register(listener2);
+        assertEquals(1, source.initCount);
+        source.offer(MY_MESSAGE + "z");
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE + "z");
+        verify(listener2).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE + "z");
+
+        // re-register - should not re-init
+        source.register(listener);
+        assertEquals(1, source.initCount);
+        source.offer(MY_MESSAGE2);
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE2);
+
+        // lock & register - should not init
+        source = new SingleThreadedBusTopicSourceImpl(makeBuilder().build());
+        source.lock();
+        source.register(listener);
+        assertEquals(0, source.initCount);
+
+        // exception during init
+        source = new SingleThreadedBusTopicSourceImpl(makeBuilder().build());
+        source.initEx = true;
+        source.register(listener);
+    }
+
+    @Test
+    void testUnregister() {
+        TopicListener listener2 = mock(TopicListener.class);
+        source.register(listener);
+        source.register(listener2);
+
+        // unregister first listener - should NOT invoke close
+        source.unregister(listener);
+        verify(cons, never()).close();
+        assertEquals(Arrays.asList(listener2), source.snapshotTopicListeners());
+
+        // unregister same listener - should not invoke close
+        source.unregister(listener);
+        verify(cons, never()).close();
+        assertEquals(Arrays.asList(listener2), source.snapshotTopicListeners());
+
+        // unregister second listener - SHOULD invoke close
+        source.unregister(listener2);
+        verify(cons).close();
+        assertTrue(source.snapshotTopicListeners().isEmpty());
+
+        // unregister same listener - should not invoke close again
+        source.unregister(listener2);
+        verify(cons).close();
+        assertTrue(source.snapshotTopicListeners().isEmpty());
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(source.toString().startsWith("SingleThreadedBusTopicSource ["));
+    }
+
+    @Test
+    void testMakePollerThread() {
+        SingleThreadedBusTopicSource source2 = new SingleThreadedBusTopicSource(makeBuilder().build()) {
+            @Override
+            public CommInfrastructure getTopicCommInfrastructure() {
+                return CommInfrastructure.NOOP;
+            }
+
+            @Override
+            public void init() throws MalformedURLException {
+                // do nothing
+            }
+        };
+
+        assertNotNull(source2.makePollerThread());
+    }
+
+    @Test
+    void testSingleThreadedBusTopicSource() {
+        // Note: if the value contains "-", it's probably a UUID
+
+        // verify that different wrappers can be built
+        source = new SingleThreadedBusTopicSourceImpl(makeBuilder().build());
+        assertThat(source.getConsumerGroup()).isEqualTo(MY_CONS_GROUP);
+        assertThat(source.getConsumerInstance()).isEqualTo(MY_CONS_INST);
+
+        // group is null => group is UUID, instance is as provided
+        source = new SingleThreadedBusTopicSourceImpl(makeBuilder().consumerGroup(null).build());
+        assertThat(source.getConsumerGroup()).contains("-").isNotEqualTo(NetworkUtil.getHostname());
+        assertThat(source.getConsumerInstance()).isEqualTo(MY_CONS_INST);
+
+        // instance is null => group is as provided, instance is UUID
+        source = new SingleThreadedBusTopicSourceImpl(makeBuilder().consumerInstance(null).build());
+        assertThat(source.getConsumerGroup()).isEqualTo(MY_CONS_GROUP);
+        assertThat(source.getConsumerInstance()).contains("-").isNotEqualTo(NetworkUtil.getHostname());
+
+        // group & instance are null => group is UUID, instance is hostname
+        source = new SingleThreadedBusTopicSourceImpl(makeBuilder().consumerGroup(null).consumerInstance(null).build());
+        assertThat(source.getConsumerGroup()).contains("-").isNotEqualTo(NetworkUtil.getHostname());
+        assertThat(source.getConsumerInstance()).isEqualTo(NetworkUtil.getHostname());
+
+        assertThatCode(() -> new SingleThreadedBusTopicSourceImpl(
+                        makeBuilder().fetchLimit(-1).fetchTimeout(-1).build())).doesNotThrowAnyException();
+    }
+
+    @Test
+    void testStart() {
+        source.start();
+        assertTrue(source.isAlive());
+        assertEquals(1, source.initCount);
+        verify(thread).start();
+
+        // attempt to start again - nothing should be invoked again
+        source.start();
+        assertTrue(source.isAlive());
+        assertEquals(1, source.initCount);
+        verify(thread).start();
+
+        // stop & re-start
+        source.stop();
+        source.start();
+        assertTrue(source.isAlive());
+        assertEquals(2, source.initCount);
+        verify(thread, times(2)).start();
+    }
+
+    @Test
+    void testStart_Locked() {
+        source.lock();
+        assertThatThrownBy(() -> source.start()).isInstanceOf(IllegalStateException.class);
+    }
+
+    @Test
+    void testStart_InitEx() {
+        assertThatThrownBy(() -> {
+            source.initEx = true;
+
+            source.start();
+        }).isInstanceOf(IllegalStateException.class);
+    }
+
+    @Test
+    void testStop() {
+        source.start();
+        source.stop();
+        verify(cons).close();
+
+        // stop it again - not re-closed
+        source.stop();
+        verify(cons).close();
+
+        // start & stop again, but with an exception
+        doThrow(new RuntimeException(EXPECTED)).when(cons).close();
+        source.start();
+        source.stop();
+    }
+
+    @Test
+    void testRun() throws Exception {
+        source.register(listener);
+
+        /*
+         * Die in the middle of fetching messages. Also, throw an exception during the
+         * first fetch attempt.
+         */
+        when(cons.fetch()).thenAnswer(new Answer<Iterable<String>>() {
+            int count = 0;
+
+            @Override
+            public Iterable<String> answer(InvocationOnMock invocation) throws Throwable {
+                if (++count > 1) {
+                    source.alive = false;
+                    return Arrays.asList(MY_MESSAGE, MY_MESSAGE2);
+
+                } else {
+                    throw new IOException(EXPECTED);
+                }
+            }
+        });
+        source.alive = true;
+        source.run();
+        assertEquals(Arrays.asList(MY_MESSAGE), Arrays.asList(source.getRecentEvents()));
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE);
+        verify(listener, never()).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE2);
+
+        /*
+         * Die AFTER fetching messages.
+         */
+        final String msga = "message-A";
+        final String msgb = "message-B";
+        when(cons.fetch()).thenAnswer(new Answer<Iterable<String>>() {
+            int count = 0;
+
+            @Override
+            public Iterable<String> answer(InvocationOnMock invocation) throws Throwable {
+                if (++count > 1) {
+                    source.alive = false;
+                    return Collections.emptyList();
+
+                } else {
+                    return Arrays.asList(msga, msgb);
+                }
+            }
+        });
+        source.alive = true;
+        source.run();
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, msga);
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, msgb);
+
+        assertEquals(Arrays.asList(MY_MESSAGE, msga, msgb), Arrays.asList(source.getRecentEvents()));
+    }
+
+    @Test
+    void testOffer() {
+        source.register(listener);
+        source.offer(MY_MESSAGE);
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE);
+        assertEquals(Arrays.asList(MY_MESSAGE), Arrays.asList(source.getRecentEvents()));
+    }
+
+    @Test
+    void testOffer_NotStarted() {
+        assertThatThrownBy(() -> source.offer(MY_MESSAGE)).isInstanceOf(IllegalStateException.class);
+    }
+
+    @Test
+    void testGetConsumerGroup() {
+        assertEquals(MY_CONS_GROUP, source.getConsumerGroup());
+    }
+
+    @Test
+    void testGetConsumerInstance() {
+        assertEquals(MY_CONS_INST, source.getConsumerInstance());
+    }
+
+    @Test
+    void testShutdown() {
+        source.register(listener);
+
+        source.shutdown();
+        verify(cons).close();
+        assertTrue(source.snapshotTopicListeners().isEmpty());
+    }
+
+    @Test
+    void testGetFetchTimeout() {
+        assertEquals(MY_FETCH_TIMEOUT, source.getFetchTimeout());
+    }
+
+    @Test
+    void testGetFetchLimit() {
+        assertEquals(MY_FETCH_LIMIT, source.getFetchLimit());
+    }
+
+    /**
+     * Implementation of SingleThreadedBusTopicSource that counts the number of times
+     * init() is invoked.
+     */
+    private class SingleThreadedBusTopicSourceImpl extends SingleThreadedBusTopicSource {
+
+        private int initCount = 0;
+        private boolean initEx = false;
+
+        public SingleThreadedBusTopicSourceImpl(BusTopicParams busTopicParams) {
+            super(busTopicParams);
+        }
+
+        @Override
+        public CommInfrastructure getTopicCommInfrastructure() {
+            return CommInfrastructure.NOOP;
+        }
+
+        @Override
+        public void init() throws MalformedURLException {
+            ++initCount;
+
+            if (initEx) {
+                throw new MalformedURLException(EXPECTED);
+            }
+
+            consumer = cons;
+        }
+
+        @Override
+        protected Thread makePollerThread() {
+            return thread;
+        }
+
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicBaseTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicBaseTest.java
new file mode 100644
index 00000000..5ecde258
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicBaseTest.java
@@ -0,0 +1,355 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2018-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import java.util.Collections;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.onap.policy.common.utils.gson.GsonTestUtils;
+
+class TopicBaseTest extends TopicTestBase {
+
+    private TopicBaseImpl base;
+
+    /**
+     * Creates the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        base = new TopicBaseImpl(servers, MY_TOPIC);
+    }
+
+    @Test
+    void testTopicBase_NullServers() {
+        assertThatThrownBy(() -> new TopicBaseImpl(null, MY_TOPIC)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testTopicBase_EmptyServers() {
+        List<String> testList = Collections.emptyList();
+        assertThatThrownBy(() -> new TopicBaseImpl(testList, MY_TOPIC))
+            .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testTopicBase_NullTopic() {
+        assertThatThrownBy(() -> new TopicBaseImpl(servers, null)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testTopicBase_EmptyTopic() {
+        assertThatThrownBy(() -> new TopicBaseImpl(servers, "")).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testTopicBase_EffectiveTopic() {
+        TopicBase baseEf = new TopicBaseImpl(servers, MY_TOPIC, MY_EFFECTIVE_TOPIC);
+        assertEquals(MY_TOPIC, baseEf.getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, baseEf.getEffectiveTopic());
+    }
+
+    @Test
+    void testTopicBase_NullEffectiveTopic() {
+        TopicBase baseEf = new TopicBaseImpl(servers, MY_TOPIC, null);
+        assertEquals(MY_TOPIC, baseEf.getTopic());
+        assertEquals(MY_TOPIC, baseEf.getEffectiveTopic());
+    }
+
+    @Test
+    void testTopicBase_EmptyEffectiveTopic() {
+        TopicBase baseEf = new TopicBaseImpl(servers, MY_TOPIC, "");
+        assertEquals(MY_TOPIC, baseEf.getTopic());
+        assertEquals(MY_TOPIC, baseEf.getEffectiveTopic());
+    }
+
+    @Test
+    void testSerialize() {
+        assertThatCode(() -> new GsonTestUtils().compareGson(base, TopicBaseTest.class)).doesNotThrowAnyException();
+    }
+
+    @Test
+    void testRegister() {
+        TopicListener listener = mock(TopicListener.class);
+        base.register(listener);
+        assertEquals(List.of(listener), base.snapshotTopicListeners());
+
+        // re-register - list should be unchanged
+        base.register(listener);
+        assertEquals(List.of(listener), base.snapshotTopicListeners());
+
+        // register a new listener
+        TopicListener listener2 = mock(TopicListener.class);
+        base.register(listener2);
+        assertEquals(List.of(listener, listener2), base.snapshotTopicListeners());
+    }
+
+    @Test
+    void testRegister_NullListener() {
+        assertThatThrownBy(() -> base.register(null)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testUnregister() {
+        // register two listeners
+        TopicListener listener = mock(TopicListener.class);
+        TopicListener listener2 = mock(TopicListener.class);
+        base.register(listener);
+        base.register(listener2);
+
+        // unregister one
+        base.unregister(listener);
+        assertEquals(List.of(listener2), base.snapshotTopicListeners());
+
+        // unregister the other
+        base.unregister(listener2);
+        assertTrue(base.snapshotTopicListeners().isEmpty());
+
+        // unregister again
+        base.unregister(listener2);
+        assertTrue(base.snapshotTopicListeners().isEmpty());
+    }
+
+    @Test
+    void testUnregister_NullListener() {
+        base.register(mock(TopicListener.class));
+        assertThatThrownBy(() -> base.unregister(null)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testBroadcast() {
+        // register two listeners
+        TopicListener listener = mock(TopicListener.class);
+        TopicListener listener2 = mock(TopicListener.class);
+        base.register(listener);
+        base.register(listener2);
+
+        // broadcast a message
+        final String msg1 = "message-A";
+        base.broadcast(msg1);
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, msg1);
+        verify(listener2).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, msg1);
+
+        // broadcast another message, with an exception
+        final String msg2 = "message-B";
+        doThrow(new RuntimeException(EXPECTED)).when(listener).onTopicEvent(any(), any(), any());
+        base.broadcast(msg2);
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, msg2);
+        verify(listener2).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, msg2);
+    }
+
+    @Test
+    void testLock_testUnlock() {
+        assertFalse(base.isLocked());
+        assertTrue(base.lock());
+        assertEquals(0, base.startCount);
+        assertEquals(1, base.stopCount);
+
+        // lock again - should not stop again
+        assertTrue(base.isLocked());
+        assertTrue(base.lock());
+        assertEquals(0, base.startCount);
+        assertEquals(1, base.stopCount);
+
+        assertTrue(base.isLocked());
+        assertTrue(base.unlock());
+        assertEquals(1, base.startCount);
+        assertEquals(1, base.stopCount);
+
+        // unlock again - should not start again
+        assertFalse(base.isLocked());
+        assertTrue(base.unlock());
+        assertEquals(1, base.startCount);
+        assertEquals(1, base.stopCount);
+    }
+
+    /**
+     * Tests lock/unlock when the stop/start methods return false.
+     */
+    @Test
+    void testLock_testUnlock_FalseReturns() {
+
+        // lock, but stop returns false
+        base.stopReturn = false;
+        assertFalse(base.lock());
+        assertTrue(base.isLocked());
+        assertTrue(base.lock());
+
+        // unlock, but start returns false
+        base.startReturn = false;
+        assertFalse(base.unlock());
+        assertFalse(base.isLocked());
+        assertTrue(base.unlock());
+    }
+
+    /**
+     * Tests lock/unlock when the start method throws an exception.
+     */
+    @Test
+    void testLock_testUnlock_Exception() {
+
+        // lock & re-lock, but start throws an exception
+        base.startEx = true;
+        assertTrue(base.lock());
+        assertFalse(base.unlock());
+        assertFalse(base.isLocked());
+        assertTrue(base.unlock());
+    }
+
+    @Test
+    void testIsLocked() {
+        assertFalse(base.isLocked());
+        base.lock();
+        assertTrue(base.isLocked());
+        base.unlock();
+        assertFalse(base.isLocked());
+    }
+
+    @Test
+    void testGetTopic() {
+        assertEquals(MY_TOPIC, base.getTopic());
+    }
+
+    @Test
+    void testGetEffectiveTopic() {
+        assertEquals(MY_TOPIC, base.getTopic());
+        assertEquals(MY_TOPIC, base.getEffectiveTopic());
+    }
+
+    @Test
+    void testIsAlive() {
+        assertFalse(base.isAlive());
+        base.start();
+        assertTrue(base.isAlive());
+        base.stop();
+        assertFalse(base.isAlive());
+    }
+
+    @Test
+    void testGetServers() {
+        assertEquals(servers, base.getServers());
+    }
+
+    @Test
+    void testGetRecentEvents() {
+        assertEquals(0, base.getRecentEvents().length);
+
+        base.addEvent("recent-A");
+        base.addEvent("recent-B");
+
+        String[] recent = base.getRecentEvents();
+        assertEquals(2, recent.length);
+        assertEquals("recent-A", recent[0]);
+        assertEquals("recent-B", recent[1]);
+    }
+
+    @Test
+    void testToString() {
+        assertNotNull(base.toString());
+    }
+
+    /**
+     * Implementation of TopicBase.
+     */
+    private static class TopicBaseImpl extends TopicBase {
+        private int startCount = 0;
+        private int stopCount = 0;
+        private boolean startReturn = true;
+        private boolean stopReturn = true;
+        private boolean startEx = false;
+
+        /**
+         * Constructor.
+         *
+         * @param servers list of servers
+         * @param topic topic name
+         */
+        public TopicBaseImpl(List<String> servers, String topic) {
+            super(servers, topic);
+        }
+
+        /**
+         * Constructor.
+         *
+         * @param servers list of servers
+         * @param topic topic name
+         * @param effectiveTopic effective topic name for network communication
+         */
+        public TopicBaseImpl(List<String> servers, String topic, String effectiveTopic) {
+            super(servers, topic, effectiveTopic);
+        }
+
+        @Override
+        public CommInfrastructure getTopicCommInfrastructure() {
+            return CommInfrastructure.NOOP;
+        }
+
+        @Override
+        public boolean start() {
+            ++startCount;
+
+            if (startEx) {
+                throw new RuntimeException(EXPECTED);
+            }
+
+            alive = true;
+            return startReturn;
+        }
+
+        @Override
+        public boolean stop() {
+            ++stopCount;
+            alive = false;
+            return stopReturn;
+        }
+
+        @Override
+        public void shutdown() {
+            // do nothing
+        }
+
+        /**
+         * Adds an event to the list of recent events.
+         *
+         * @param event event to be added
+         */
+        public void addEvent(String event) {
+            recentEvents.add(event);
+        }
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicFactoryTestBase.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicFactoryTestBase.java
new file mode 100644
index 00000000..8444b482
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicFactoryTestBase.java
@@ -0,0 +1,225 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SERVERS_SUFFIX;
+
+import java.util.List;
+import java.util.Properties;
+import org.onap.policy.common.message.bus.event.Topic;
+
+/**
+ * Base class for XxxTopicFactory tests.
+ *
+ * @param <T> type of topic managed by the factory
+ */
+public abstract class TopicFactoryTestBase<T extends Topic> extends TopicTestBase {
+
+    public static final String SERVER = "my-server";
+    public static final String TOPIC2 = "my-topic-2";
+    public static final String TOPIC3 = "my-topic-3";
+
+    /**
+     * Initializes a new factory.
+     */
+    protected abstract void initFactory();
+
+    /**
+     * Makes a property builder.
+     *
+     * @return a new property builder
+     */
+    protected abstract TopicPropertyBuilder makePropBuilder();
+
+    /**
+     * Builds a set of topics.
+     *
+     * @param properties the properties used to configure the topics
+     * @return a list of new topics
+     */
+    protected abstract List<T> buildTopics(Properties properties);
+
+    /**
+     * Destroys the factory.
+     */
+    protected abstract void destroyFactory();
+
+    /**
+     * Destroys a topic within the factory.
+     *
+     * @param topic the topic to destroy
+     */
+    protected abstract void destroyTopic(String topic);
+
+    /**
+     * Gets the list of topics from the factory.
+     *
+     * @return the topic inventory
+     */
+    protected abstract List<T> getInventory();
+
+    /**
+     * Gets a topic from the factory.
+     *
+     * @param topic the topic name
+     * @return the topic
+     */
+    protected abstract T getTopic(String topic);
+
+
+    /**
+     * Tests building a topic using varied Properties.
+     */
+    void testBuildProperties_Variations() {
+        initFactory();
+
+        // null topic list
+        assertTrue(buildTopics(makePropBuilder().build()).isEmpty());
+
+        // empty topic list
+        assertTrue(buildTopics(makePropBuilder().addTopic("").build()).isEmpty());
+
+        // null servers
+        assertTrue(buildTopics(makePropBuilder().makeTopic(MY_TOPIC).removeTopicProperty(PROPERTY_TOPIC_SERVERS_SUFFIX)
+            .build()).isEmpty());
+
+        // empty servers
+        assertTrue(buildTopics(makePropBuilder().makeTopic(MY_TOPIC).setTopicProperty(PROPERTY_TOPIC_SERVERS_SUFFIX, "")
+            .build()).isEmpty());
+    }
+
+    /**
+     * Tests building multiple topics using Properties.
+     */
+    public void testBuildProperties_Multiple() {
+        initFactory();
+
+        // make two fully-defined topics, and add two duplicate topic names to the list
+        TopicPropertyBuilder builder =
+            makePropBuilder().makeTopic(MY_TOPIC).makeTopic(TOPIC2).addTopic(MY_TOPIC).addTopic(MY_TOPIC);
+
+        List<T> lst = buildTopics(builder.build());
+        assertEquals(4, lst.size());
+
+        int index = 0;
+        T item = lst.get(index++);
+        assertNotSame(item, lst.get(index++));
+        assertSame(item, lst.get(index++));
+        assertSame(item, lst.get(index++));
+    }
+
+    /**
+     * Tests destroy(topic), get(topic), and inventory() methods.
+     */
+    public void testDestroyString_testGet_testInventory() {
+        initFactory();
+
+        List<T> lst = buildTopics(makePropBuilder().makeTopic(MY_TOPIC).makeTopic(TOPIC2).build());
+
+        int index = 0;
+        T item1 = lst.get(index++);
+        T item2 = lst.get(index++);
+
+        assertEquals(2, getInventory().size());
+        assertTrue(getInventory().contains(item1));
+        assertTrue(getInventory().contains(item2));
+
+        item1.start();
+        item2.start();
+
+        assertEquals(item1, getTopic(MY_TOPIC));
+        assertEquals(item2, getTopic(TOPIC2));
+
+        destroyTopic(MY_TOPIC);
+        assertFalse(item1.isAlive());
+        assertTrue(item2.isAlive());
+        assertEquals(item2, getTopic(TOPIC2));
+        assertEquals(1, getInventory().size());
+        assertTrue(getInventory().contains(item2));
+
+        // repeat
+        destroyTopic(MY_TOPIC);
+        assertFalse(item1.isAlive());
+        assertTrue(item2.isAlive());
+
+        // with other topic
+        destroyTopic(TOPIC2);
+        assertFalse(item1.isAlive());
+        assertFalse(item2.isAlive());
+        assertEquals(0, getInventory().size());
+    }
+
+    /**
+     * Tests exception cases with destroy(topic).
+     */
+    public void testDestroyString_Ex() {
+        // null topic
+        assertThatIllegalArgumentException().as("null topic").isThrownBy(() -> destroyTopic(null));
+
+        // empty topic
+        assertThatIllegalArgumentException().as("empty topic").isThrownBy(() -> destroyTopic(""));
+    }
+
+    /**
+     * Tests the destroy() method.
+     */
+    public void testDestroy() {
+        initFactory();
+
+        List<T> lst = buildTopics(makePropBuilder().makeTopic(MY_TOPIC).makeTopic(TOPIC2).build());
+
+        int index = 0;
+        T item1 = lst.get(index++);
+        T item2 = lst.get(index++);
+
+        item1.start();
+        item2.start();
+
+        destroyFactory();
+
+        assertFalse(item1.isAlive());
+        assertFalse(item2.isAlive());
+        assertEquals(0, getInventory().size());
+    }
+
+    /**
+     * Tests exception cases with get(topic).
+     */
+    public void testGet_Ex() {
+        // null topic
+        assertThatIllegalArgumentException().as("null topic").isThrownBy(() -> getTopic(null));
+
+        // empty topic
+        assertThatIllegalArgumentException().as("empty topic").isThrownBy(() -> getTopic(""));
+
+        // unknown topic
+        initFactory();
+        buildTopics(makePropBuilder().makeTopic(MY_TOPIC).build());
+
+        assertThatIllegalStateException().as("unknown topic").isThrownBy(() -> getTopic(TOPIC2));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicPropertyBuilder.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicPropertyBuilder.java
new file mode 100644
index 00000000..29c5306b
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicPropertyBuilder.java
@@ -0,0 +1,121 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Engine - Common Modules
+ * ================================================================================
+ * Copyright (C) 2018 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import java.util.Properties;
+
+/**
+ * Builder of properties used when configuring topics.
+ */
+public abstract class TopicPropertyBuilder {
+    private final Properties properties = new Properties();
+    private final String prefix;
+    private String topicPrefix;
+
+    /**
+     * Constructs the object.
+     *
+     * @param prefix the prefix for the properties to be built
+     */
+    public TopicPropertyBuilder(String prefix) {
+        this.prefix = prefix;
+    }
+
+    /**
+     * Constructs the properties from the builder.
+     *
+     * @return a copy of the properties
+     */
+    public Properties build() {
+        Properties props = new Properties();
+        props.putAll(properties);
+
+        return props;
+    }
+
+    /**
+     * Adds a topic to the list of topics, configuring all of its properties with default
+     * values.
+     * 
+     * @param topic the topic to be added
+     * @return this builder
+     */
+    public abstract TopicPropertyBuilder makeTopic(String topic);
+
+    /**
+     * Adds a topic to the list of topics. Also sets the current topic so that subsequent
+     * invocations of property methods will manipulate the topic's properties.
+     *
+     * @param topic the topic to be added
+     * @return this builder
+     */
+    public TopicPropertyBuilder addTopic(String topic) {
+        // add topic to the list of topics
+        String topicList = properties.getProperty(prefix);
+        if (topicList == null || topicList.isEmpty()) {
+            topicList = topic;
+        } else {
+            topicList += "," + topic;
+        }
+
+        properties.setProperty(prefix, topicList);
+
+        setTopic(topic);
+
+        return this;
+    }
+
+    /**
+     * Sets the topic for which subsequent properties will be managed.
+     *
+     * @param topic the topic
+     * @return this builder
+     */
+    public TopicPropertyBuilder setTopic(String topic) {
+        this.topicPrefix = prefix + "." + topic;
+        return this;
+    }
+
+    /**
+     * Sets a topic's property.
+     *
+     * @param name name of the property
+     * @param value value to which the property should be set
+     * @return this builder
+     */
+    public TopicPropertyBuilder setTopicProperty(String name, Object value) {
+        properties.setProperty(topicPrefix + name, value.toString());
+        return this;
+    }
+
+    /**
+     * Removes a topic's property.
+     *
+     * @param name name of the property
+     * @return this builder
+     */
+    public TopicPropertyBuilder removeTopicProperty(String name) {
+        properties.remove(topicPrefix + name);
+        return this;
+    }
+}
+
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicTestBase.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicTestBase.java
new file mode 100644
index 00000000..8d5c3535
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/base/TopicTestBase.java
@@ -0,0 +1,159 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.base;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+import org.onap.policy.common.parameters.topic.BusTopicParams.TopicParamsBuilder;
+
+/**
+ * Base class for Topic Test classes.
+ */
+public class TopicTestBase {
+
+    public static final String MY_AFT_ENV = "my-aft-env";
+    public static final String MY_API_KEY = "my-api-key";
+    public static final String MY_API_SECRET = "my-api-secret";
+    public static final String MY_BASE_PATH = "my-base";
+    public static final String MY_CLIENT_NAME = "my-client";
+    public static final String MY_CONS_GROUP = "my-cons-group";
+    public static final String MY_CONS_INST = "my-cons-inst";
+    public static final String MY_ENV = "my-env";
+    public static final int MY_FETCH_LIMIT = 100;
+    public static final int MY_FETCH_TIMEOUT = 101;
+    public static final String MY_HOST = "my-host";
+    public static final String MY_LAT = "my-lat";
+    public static final String MY_LONG = "my-long";
+    public static final String MY_PARTNER = "my-partner";
+    public static final String MY_PASS = "my-pass";
+    public static final int MY_PORT = 102;
+    public static final String MY_TOPIC = "my-topic";
+    public static final String MY_EFFECTIVE_TOPIC = "my-effective-topic";
+    public static final String MY_USERNAME = "my-user";
+
+    public static final String MY_MESSAGE = "my-message";
+    public static final String MY_PARTITION = "my-partition";
+    public static final String MY_MESSAGE2 = "my-message-2";
+
+    public static final String MY_SERIALIZER = "org.apache.kafka.common.serialization.StringSerializer";
+    public static final int KAFKA_PORT = 9092;
+
+    /**
+     * Message used within exceptions that are expected.
+     */
+    public static final String EXPECTED = "expected exception";
+
+    /**
+     * Additional properties to be added to the parameter builder.
+     */
+    protected Map<String, String> addProps;
+
+    /**
+     * Servers to be added to the parameter builder.
+     */
+    protected List<String> servers;
+
+    /**
+     * Servers to be added to the parameter builder.
+     */
+    protected List<String> kafkaServers;
+
+    /**
+     * Parameter builder used to build topic parameters.
+     */
+    protected TopicParamsBuilder builder;
+
+    /**
+     * Initializes {@link #addProps}, {@link #servers}, and {@link #builder}.
+     */
+    public void setUp() {
+        addProps = new TreeMap<>();
+        addProps.put("my-key-A", "my-value-A");
+        addProps.put("my-key-B", "my-value-B");
+
+        servers = Arrays.asList("svra", "svrb");
+        kafkaServers = Arrays.asList("localhost:9092", "10.1.2.3:9092");
+
+        builder = makeBuilder();
+    }
+
+    /**
+     * Makes a fully populated parameter builder.
+     *
+     * @return a new parameter builder
+     */
+    public TopicParamsBuilder makeBuilder() {
+        return makeBuilder(addProps, servers);
+    }
+
+    /**
+     * Makes a fully populated parameter builder.
+     * 
+     * @param addProps additional properties to be added to the builder
+     * @param servers servers to be added to the builder
+     * @return a new parameter builder
+     */
+    public TopicParamsBuilder makeBuilder(Map<String, String> addProps, List<String> servers) {
+
+        return BusTopicParams.builder().additionalProps(addProps).aftEnvironment(MY_AFT_ENV).allowSelfSignedCerts(true)
+                        .apiKey(MY_API_KEY).apiSecret(MY_API_SECRET).basePath(MY_BASE_PATH).clientName(MY_CLIENT_NAME)
+                        .consumerGroup(MY_CONS_GROUP).consumerInstance(MY_CONS_INST).environment(MY_ENV)
+                        .fetchLimit(MY_FETCH_LIMIT).fetchTimeout(MY_FETCH_TIMEOUT).hostname(MY_HOST).latitude(MY_LAT)
+                        .longitude(MY_LONG).managed(true).partitionId(MY_PARTITION).partner(MY_PARTNER)
+                        .password(MY_PASS).port(MY_PORT).servers(servers).topic(MY_TOPIC)
+                        .effectiveTopic(MY_EFFECTIVE_TOPIC).useHttps(true).allowTracing(true).userName(MY_USERNAME)
+                        .serializationProvider(MY_SERIALIZER);
+    }
+
+    /**
+     * Makes a fully populated parameter builder.
+     *
+     * @return a new parameter builder
+     */
+    public TopicParamsBuilder makeKafkaBuilder() {
+        addProps.clear();
+        String jaas = "org.apache.kafka.common.security.plain.PlainLoginModule "
+            + "required username=abc password=abc serviceName=kafka;";
+        addProps.put("sasl.jaas.config", jaas);
+        addProps.put("sasl.mechanism", "SCRAM-SHA-512");
+        addProps.put("security.protocol", "SASL_PLAINTEXT");
+
+        return makeKafkaBuilder(addProps, kafkaServers);
+    }
+
+    /**
+     * Makes a fully populated parameter builder.
+     *
+     * @param addProps additional properties to be added to the builder
+     * @param servers servers to be added to the builder
+     * @return a new parameter builder
+     */
+    public TopicParamsBuilder makeKafkaBuilder(Map<String, String> addProps, List<String> servers) {
+
+        return BusTopicParams.builder().additionalProps(addProps).basePath(MY_BASE_PATH).clientName(MY_CLIENT_NAME)
+                        .consumerGroup(MY_CONS_GROUP).consumerInstance(MY_CONS_INST).environment(MY_ENV)
+                        .hostname(MY_HOST).partitionId(MY_PARTITION).partner(MY_PARTNER).fetchTimeout(MY_FETCH_TIMEOUT)
+                        .port(KAFKA_PORT).servers(servers).topic(MY_TOPIC)
+                        .effectiveTopic(MY_EFFECTIVE_TOPIC).useHttps(false).allowTracing(true);
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClientTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClientTest.java
new file mode 100644
index 00000000..ba33ff9a
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/BidirectionalTopicClientTest.java
@@ -0,0 +1,454 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2020-2021 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.client;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.atLeast;
+import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.Arrays;
+import java.util.Properties;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.TopicEndpoint;
+import org.onap.policy.common.message.bus.event.TopicEndpointManager;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.onap.policy.common.message.bus.event.TopicSink;
+import org.onap.policy.common.message.bus.event.TopicSource;
+import org.onap.policy.common.utils.coder.Coder;
+import org.onap.policy.common.utils.coder.CoderException;
+import org.onap.policy.common.utils.coder.StandardCoder;
+
+@ExtendWith(MockitoExtension.class)
+class BidirectionalTopicClientTest {
+    private static final Coder coder = new StandardCoder();
+    private static final long MAX_WAIT_MS = 5000;
+    private static final long SHORT_WAIT_MS = 1;
+    private static final String SINK_TOPIC = "my-sink-topic";
+    private static final String SOURCE_TOPIC = "my-source-topic";
+    private static final String MY_TEXT = "my-text";
+
+    private static final CommInfrastructure SINK_INFRA = CommInfrastructure.NOOP;
+    private static final CommInfrastructure SOURCE_INFRA = CommInfrastructure.NOOP;
+
+    @Mock
+    private TopicSink sink;
+    @Mock
+    private TopicSource source;
+    @Mock
+    private TopicEndpoint endpoint;
+    @Mock
+    private TopicListener listener;
+
+    private MyMessage theMessage;
+
+    private BidirectionalTopicClient client;
+    private Context context;
+
+    /**
+     * Configures the endpoints.
+     */
+    @BeforeAll
+    public static void setUpBeforeClass() {
+        Properties props = new Properties();
+        props.setProperty("noop.sink.topics", SINK_TOPIC);
+        props.setProperty("noop.source.topics", SOURCE_TOPIC);
+
+        // clear all topics and then configure one sink and one source
+        TopicEndpointManager.getManager().shutdown();
+        TopicEndpointManager.getManager().addTopicSinks(props);
+        TopicEndpointManager.getManager().addTopicSources(props);
+    }
+
+    @AfterAll
+    public static void tearDownAfterClass() {
+        // clear all topics after the tests
+        TopicEndpointManager.getManager().shutdown();
+    }
+
+    /**
+     * Creates mocks and an initial client object.
+     */
+    @BeforeEach
+    public void setUp() throws Exception {
+        lenient().when(sink.send(anyString())).thenReturn(true);
+        lenient().when(sink.getTopicCommInfrastructure()).thenReturn(SINK_INFRA);
+
+        lenient().when(source.offer(anyString())).thenReturn(true);
+        lenient().when(source.getTopicCommInfrastructure()).thenReturn(SOURCE_INFRA);
+
+        lenient().when(endpoint.getTopicSinks(anyString())).thenReturn(Arrays.asList());
+        lenient().when(endpoint.getTopicSinks(SINK_TOPIC)).thenReturn(Arrays.asList(sink));
+
+        lenient().when(endpoint.getTopicSources(any())).thenReturn(Arrays.asList());
+        lenient().when(endpoint.getTopicSources(Arrays.asList(SOURCE_TOPIC))).thenReturn(Arrays.asList(source));
+
+        theMessage = new MyMessage(MY_TEXT);
+
+        client = new BidirectionalTopicClient2(SINK_TOPIC, SOURCE_TOPIC);
+
+        context = new Context();
+    }
+
+    @AfterEach
+    public void tearDown() {
+        context.stop();
+    }
+
+    @Test
+    void testBidirectionalTopicClient_testGetters() {
+        assertSame(sink, client.getSink());
+        assertSame(source, client.getSource());
+        assertEquals(SINK_TOPIC, client.getSinkTopic());
+        assertEquals(SOURCE_TOPIC, client.getSourceTopic());
+        assertEquals(SINK_INFRA, client.getSinkTopicCommInfrastructure());
+        assertEquals(SOURCE_INFRA, client.getSourceTopicCommInfrastructure());
+    }
+
+    /**
+     * Tests the constructor when the sink or source cannot be found.
+     */
+    @Test
+    void testBidirectionalTopicClientExceptions() {
+        assertThatThrownBy(() -> new BidirectionalTopicClient2("unknown-sink", SOURCE_TOPIC))
+            .isInstanceOf(BidirectionalTopicClientException.class)
+            .hasMessage("no sinks for topic: unknown-sink");
+
+        assertThatThrownBy(() -> new BidirectionalTopicClient2(SINK_TOPIC, "unknown-source"))
+            .isInstanceOf(BidirectionalTopicClientException.class)
+            .hasMessage("no sources for topic: unknown-source");
+
+        // too many sources
+        when(endpoint.getTopicSources(Arrays.asList(SOURCE_TOPIC))).thenReturn(Arrays.asList(source, source));
+
+        assertThatThrownBy(() -> new BidirectionalTopicClient2(SINK_TOPIC, SOURCE_TOPIC))
+            .isInstanceOf(BidirectionalTopicClientException.class)
+            .hasMessage("too many sources for topic: my-source-topic");
+    }
+
+    /**
+     * Tests the "delegate" methods.
+     */
+    @Test
+    void testDelegates() {
+        assertTrue(client.send("hello"));
+        verify(sink).send("hello");
+
+        assertTrue(client.offer("incoming"));
+        verify(source).offer("incoming");
+
+        client.register(listener);
+        verify(source).register(listener);
+
+        client.unregister(listener);
+        verify(source).unregister(listener);
+    }
+
+    @Test
+    void testGetTopicEndpointManager() throws BidirectionalTopicClientException {
+        // use a real manager
+        client = new BidirectionalTopicClient(SINK_TOPIC, SOURCE_TOPIC);
+        assertNotNull(client.getTopicEndpointManager());
+
+        assertNotNull(client.getSink());
+        assertNotNull(client.getSource());
+
+        assertNotSame(sink, client.getSink());
+        assertNotSame(source, client.getSource());
+    }
+
+    @Test
+    void testAwaitReceipt() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        verify(source).register(any());
+        verify(sink, atLeast(1)).send(any());
+        assertThat(context.checker.isReady()).isFalse();
+
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    void testAwaitReceipt_AlreadyDone() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        inject(theMessage);
+
+        verifyReceipt();
+
+        // calling again should result in "true" again, without injecting message
+        context.start(theMessage);
+        verifyReceipt();
+    }
+
+    @Test
+    void testAwaitReceipt_MessageDoesNotMatch() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        // non-matching message
+        inject("{}");
+
+        // wait for a few more calls to "send" and then inject a matching message
+        assertThat(context.awaitSend(3)).isTrue();
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    void testAwaitReceipt_DecodeFails() throws Exception {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        // force a failure and inject the message
+        context.forceDecodeFailure = true;
+        inject(theMessage);
+
+        assertThat(context.awaitDecodeFailure()).isTrue();
+
+        // no more failures
+        context.forceDecodeFailure = false;
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    void testAwaitReceipt_Interrupted() throws InterruptedException {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        context.interrupt();
+
+        verifyNoReceipt();
+    }
+
+    @Test
+    void testAwaitReceipt_MultipleLoops() throws Exception {
+        context.start(theMessage);
+
+        // wait for multiple "send" calls
+        assertThat(context.awaitSend(3)).isTrue();
+
+        inject(theMessage);
+
+        verifyReceipt();
+    }
+
+    @Test
+    void testStop() throws InterruptedException {
+        context.start(theMessage);
+        assertThat(context.awaitSend(1)).isTrue();
+
+        context.stop();
+
+        verifyNoReceipt();
+    }
+
+    /**
+     * Verifies that awaitReceipt() returns {@code true}.
+     *
+     * @throws InterruptedException if interrupted while waiting for the thread to
+     *                              terminate
+     */
+    private void verifyReceipt() throws InterruptedException {
+        assertThat(context.join()).isTrue();
+        assertThat(context.result).isTrue();
+        assertThat(context.exception).isNull();
+        assertThat(context.checker.isReady()).isTrue();
+
+        verify(source).unregister(any());
+    }
+
+    /**
+     * Verifies that awaitReceipt() returns {@code false}.
+     *
+     * @throws InterruptedException if interrupted while waiting for the thread to
+     *                              terminate
+     */
+    private void verifyNoReceipt() throws InterruptedException {
+        assertThat(context.join()).isTrue();
+        assertThat(context.result).isFalse();
+        assertThat(context.exception).isNull();
+        assertThat(context.checker.isReady()).isFalse();
+
+        verify(source).unregister(any());
+    }
+
+    /**
+     * Injects a message into the source topic.
+     *
+     * @param message message to be injected
+     * @throws CoderException if the message cannot be encoded
+     */
+    private void inject(MyMessage message) throws CoderException {
+        inject(coder.encode(message));
+    }
+
+    /**
+     * Injects a message into the source topic.
+     *
+     * @param message message to be injected
+     */
+    private void inject(String message) {
+        ArgumentCaptor<TopicListener> cap = ArgumentCaptor.forClass(TopicListener.class);
+        verify(source).register(cap.capture());
+
+        cap.getValue().onTopicEvent(SOURCE_INFRA, SOURCE_TOPIC, message);
+    }
+
+
+    /**
+     * BidirectionalTopicClient with some overrides.
+     */
+    private class BidirectionalTopicClient2 extends BidirectionalTopicClient {
+
+        public BidirectionalTopicClient2(String sinkTopic, String sourceTopic)
+            throws BidirectionalTopicClientException {
+            super(sinkTopic, sourceTopic);
+        }
+
+        @Override
+        protected TopicEndpoint getTopicEndpointManager() {
+            return endpoint;
+        }
+    }
+
+    private class Context {
+        private Thread thread;
+        private boolean result;
+        private Exception exception;
+        private boolean forceDecodeFailure;
+
+        // released every time the checker publishes a message
+        private final Semaphore sendSem = new Semaphore(0);
+
+        // released every time a message-decode fails
+        private final Semaphore decodeFailedSem = new Semaphore(0);
+
+        private final BidirectionalTopicClient2 checker;
+
+        public Context() throws BidirectionalTopicClientException {
+
+            checker = new BidirectionalTopicClient2(SINK_TOPIC, SOURCE_TOPIC) {
+
+                @Override
+                public boolean send(String messageText) {
+                    boolean result = super.send(messageText);
+                    sendSem.release();
+                    return result;
+                }
+
+                @Override
+                protected <T> T decode(String msg, Class<? extends T> clazz) throws CoderException {
+                    if (forceDecodeFailure) {
+                        throw new CoderException("expected exception");
+                    }
+
+                    return super.decode(msg, clazz);
+                }
+
+                @Override
+                protected void decodeFailed() {
+                    super.decodeFailed();
+                    decodeFailedSem.release();
+                }
+            };
+        }
+
+        /**
+         * Starts the thread.
+         *
+         * @param message message to be sent to the sink topic
+         */
+        public void start(MyMessage message) {
+            thread = new Thread() {
+                @Override
+                public void run() {
+                    try {
+                        result = checker.awaitReady(message, SHORT_WAIT_MS);
+                    } catch (Exception e) {
+                        exception = e;
+                    }
+                }
+            };
+            thread.setDaemon(true);
+            thread.start();
+        }
+
+        public void stop() {
+            checker.stopWaiting();
+        }
+
+        public boolean join() throws InterruptedException {
+            thread.join(MAX_WAIT_MS);
+            return !thread.isAlive();
+        }
+
+        public void interrupt() {
+            thread.interrupt();
+        }
+
+        public boolean awaitSend(int npermits) throws InterruptedException {
+            return sendSem.tryAcquire(npermits, MAX_WAIT_MS, TimeUnit.MILLISECONDS);
+        }
+
+        public boolean awaitDecodeFailure() throws InterruptedException {
+            return decodeFailedSem.tryAcquire(MAX_WAIT_MS, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class MyMessage {
+        private String text;
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/TopicClientExceptionTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/TopicClientExceptionTest.java
new file mode 100644
index 00000000..1ea2f1bc
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/TopicClientExceptionTest.java
@@ -0,0 +1,36 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP PAP
+ * ================================================================================
+ * Copyright (C) 2019-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2019, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.client;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.utils.test.ExceptionsTester;
+
+class TopicClientExceptionTest {
+
+    @Test
+    void test() {
+        assertEquals(5, new ExceptionsTester().test(TopicSinkClientException.class));
+        assertEquals(5, new ExceptionsTester().test(BidirectionalTopicClientException.class));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/TopicSinkClientTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/TopicSinkClientTest.java
new file mode 100644
index 00000000..67b15ec9
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/client/TopicSinkClientTest.java
@@ -0,0 +1,147 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP PAP
+ * ================================================================================
+ * Copyright (C) 2019-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2019, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.client;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Properties;
+import java.util.concurrent.atomic.AtomicReference;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.TopicEndpointManager;
+import org.onap.policy.common.message.bus.event.TopicSink;
+
+class TopicSinkClientTest {
+    private static final String TOPIC = "my-topic";
+
+    private TopicSinkClient client;
+    private TopicSink sink;
+    private List<TopicSink> sinks;
+
+    /**
+     * Creates mocks and an initial client object.
+     *
+     * @throws Exception if an error occurs
+     */
+    @BeforeEach
+    public void setUp() throws Exception {
+        sink = mock(TopicSink.class);
+        when(sink.send(anyString())).thenReturn(true);
+
+        sinks = Arrays.asList(sink, null);
+
+        client = new TopicSinkClient2(TOPIC);
+
+        Properties props = new Properties();
+        props.setProperty("noop.sink.topics", TOPIC);
+
+        // clear all topics and then configure one topic
+        TopicEndpointManager.getManager().shutdown();
+        TopicEndpointManager.getManager().addTopicSinks(props);
+    }
+
+    @AfterAll
+    public static void tearDown() {
+        // clear all topics after the tests
+        TopicEndpointManager.getManager().shutdown();
+    }
+
+    /**
+     * Uses a real NO-OP topic sink.
+     */
+    @Test
+    void testGetTopicSinks() throws Exception {
+
+        sink = TopicEndpointManager.getManager().getNoopTopicSink(TOPIC);
+        assertNotNull(sink);
+
+        final AtomicReference<String> evref = new AtomicReference<>(null);
+
+        sink.register((infra, topic, event) -> evref.set(event));
+        sink.start();
+
+        client = new TopicSinkClient(TOPIC);
+        client.send(100);
+
+        assertEquals("100", evref.get());
+    }
+
+    @Test
+    void testTopicSinkClient() {
+        // unknown topic -> should throw exception
+        sinks = new LinkedList<>();
+        assertThatThrownBy(() -> new TopicSinkClient2(TOPIC)).isInstanceOf(TopicSinkClientException.class)
+            .hasMessage("no sinks for topic: my-topic");
+    }
+
+    @Test
+    void testTopicSinkClient_GetTopic() throws TopicSinkClientException {
+        assertEquals(TOPIC, new TopicSinkClient(TopicEndpointManager.getManager().getNoopTopicSink(TOPIC)).getTopic());
+        assertEquals(TOPIC, new TopicSinkClient(TOPIC).getTopic());
+
+        assertThatThrownBy(() -> new TopicSinkClient((TopicSink) null))
+            .hasMessageContaining("sink is marked non-null but is null");
+        assertThatThrownBy(() -> new TopicSinkClient("blah")).isInstanceOf(TopicSinkClientException.class)
+            .hasMessage("no sinks for topic: blah");
+    }
+
+    @Test
+    void testSend() {
+        client.send(Arrays.asList("abc", "def"));
+        verify(sink).send("['abc','def']".replace('\'', '"'));
+
+        // sink send fails
+        when(sink.send(anyString())).thenReturn(false);
+        assertFalse(client.send("ghi"));
+
+        // sink send throws an exception
+        final RuntimeException ex = new RuntimeException("expected exception");
+        when(sink.send(anyString())).thenThrow(ex);
+        assertFalse(client.send("jkl"));
+    }
+
+    /**
+     * TopicSinkClient with some overrides.
+     */
+    private class TopicSinkClient2 extends TopicSinkClient {
+
+        public TopicSinkClient2(final String topic) throws TopicSinkClientException {
+            super(topic);
+        }
+
+        @Override
+        protected List<TopicSink> getTopicSinks(final String topic) {
+            return sinks;
+        }
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSourceFactoryTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSourceFactoryTest.java
new file mode 100644
index 00000000..a901b07b
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/IndexedKafkaTopicSourceFactoryTest.java
@@ -0,0 +1,63 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+class IndexedKafkaTopicSourceFactoryTest {
+
+    private IndexedKafkaTopicSourceFactory factory;
+
+    @Test
+    void testBuild() {
+        factory = new IndexedKafkaTopicSourceFactory();
+        BusTopicParams params = new BusTopicParams();
+
+        // set servers to null
+        params.setServers(null);
+        assertThatThrownBy(() -> factory.build(params))
+            .isInstanceOf(IllegalArgumentException.class)
+            .hasMessageContaining("KAFKA Server(s) must be provided");
+
+        // set servers to empty
+        params.setServers(List.of());
+        assertThatThrownBy(() -> factory.build(params))
+            .isInstanceOf(IllegalArgumentException.class)
+            .hasMessageContaining("KAFKA Server(s) must be provided");
+
+        List<String> servers = List.of("kafka:9092", "kafka:29092");
+        params.setServers(servers);
+
+        // set topic to null
+        params.setTopic(null);
+        assertThatThrownBy(() -> factory.build(params))
+            .isInstanceOf(IllegalArgumentException.class)
+            .hasMessageContaining("A topic must be provided");
+
+        // set topic to empty
+        params.setTopic("");
+        assertThatThrownBy(() -> factory.build(params))
+            .isInstanceOf(IllegalArgumentException.class)
+            .hasMessageContaining("A topic must be provided");
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/InlineKafkaTopicSinkTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/InlineKafkaTopicSinkTest.java
new file mode 100644
index 00000000..c8d6e21e
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/InlineKafkaTopicSinkTest.java
@@ -0,0 +1,68 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.base.TopicTestBase;
+
+class InlineKafkaTopicSinkTest extends TopicTestBase {
+    private InlineKafkaTopicSink sink;
+
+    /**
+     * Creates the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        sink = new InlineKafkaTopicSink(makeKafkaBuilder().build());
+    }
+
+    @AfterEach
+    public void tearDown() {
+        sink.shutdown();
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(sink.toString().startsWith("InlineKafkaTopicSink ["));
+    }
+
+    @Test
+    void testInit() {
+        // nothing null
+        sink = new InlineKafkaTopicSink(makeKafkaBuilder().build());
+        sink.init();
+        assertThatCode(() -> sink.shutdown()).doesNotThrowAnyException();
+    }
+
+    @Test
+    void testGetTopicCommInfrastructure() {
+        assertEquals(CommInfrastructure.KAFKA, sink.getTopicCommInfrastructure());
+    }
+
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaPublisherWrapperTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaPublisherWrapperTest.java
new file mode 100644
index 00000000..8e13af23
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaPublisherWrapperTest.java
@@ -0,0 +1,98 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.util.Collections;
+import java.util.Properties;
+import org.apache.kafka.clients.producer.KafkaProducer;
+import org.apache.kafka.clients.producer.Producer;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentMatchers;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+class KafkaPublisherWrapperTest {
+
+    private KafkaPublisherWrapper kafkaPublisherWrapper;
+    private Producer<String, String> mockProducer;
+    private BusTopicParams mockBusTopicParams;
+
+    @BeforeEach
+    void setUp() {
+        mockProducer = mock(KafkaProducer.class);
+        mockBusTopicParams = mock(BusTopicParams.class);
+
+        when(mockBusTopicParams.getTopic()).thenReturn("testTopic");
+        when(mockBusTopicParams.getServers()).thenReturn(Collections.singletonList("localhost:9092"));
+        when(mockBusTopicParams.isTopicInvalid()).thenReturn(false);
+        when(mockBusTopicParams.isAdditionalPropsValid()).thenReturn(false);
+        when(mockBusTopicParams.isAllowTracing()).thenReturn(false);
+
+        kafkaPublisherWrapper = new KafkaPublisherWrapper(mockBusTopicParams) {
+            private Producer<String, String> createProducer(Properties props) { // NOSONAR instance creation
+                return mockProducer;
+            }
+        };
+    }
+
+    @Test
+    void testConstructor() {
+        verify(mockBusTopicParams).getTopic();
+        verify(mockBusTopicParams).getServers();
+        verify(mockBusTopicParams).isTopicInvalid();
+        verify(mockBusTopicParams).isAdditionalPropsValid();
+        verify(mockBusTopicParams).isAllowTracing();
+    }
+
+    @Test
+    void testSendSuccess() {
+        when(mockProducer.send(ArgumentMatchers.any(ProducerRecord.class))).thenReturn(null);
+        assertTrue(kafkaPublisherWrapper.send("partitionId", "testMessage"));
+    }
+
+    @Test
+    void testSendNullMessage() {
+        IllegalArgumentException thrown = assertThrows(
+            IllegalArgumentException.class,
+            () -> kafkaPublisherWrapper.send("partitionId", null),
+            "Expected send() to throw, but it didn't"
+        );
+        assertEquals("No message provided", thrown.getMessage());
+    }
+
+    @Test
+    void testSendFailure() {
+        when(mockProducer.send(ArgumentMatchers.any(ProducerRecord.class))).thenThrow(RuntimeException.class);
+        assertTrue(kafkaPublisherWrapper.send("partitionId", "testMessage"));
+    }
+
+    @Test
+    void testClose() {
+        assertThatCode(kafkaPublisherWrapper::close).doesNotThrowAnyException();
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicFactoryTestBase.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicFactoryTestBase.java
new file mode 100644
index 00000000..1085ee90
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicFactoryTestBase.java
@@ -0,0 +1,47 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+
+import java.util.Collections;
+import org.onap.policy.common.message.bus.event.Topic;
+import org.onap.policy.common.message.bus.event.base.BusTopicFactoryTestBase;
+
+/**
+ * Base class for KafkaTopicXxxFactory tests.
+ *
+ * @param <T> type of topic managed by the factory
+ */
+public abstract class KafkaTopicFactoryTestBase<T extends Topic> extends BusTopicFactoryTestBase<T> {
+
+    @Override
+    public void testBuildBusTopicParams_Ex() {
+
+        super.testBuildBusTopicParams_Ex();
+
+        // null servers
+        assertThatIllegalArgumentException().as("null servers")
+                        .isThrownBy(() -> buildTopic(makeBuilder().servers(null).build()));
+
+        // empty servers
+        assertThatIllegalArgumentException().as("empty servers")
+                        .isThrownBy(() -> buildTopic(makeBuilder().servers(Collections.emptyList()).build()));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicPropertyBuilder.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicPropertyBuilder.java
new file mode 100644
index 00000000..6a1be7a0
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicPropertyBuilder.java
@@ -0,0 +1,94 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.onap.policy.common.message.bus.event.base.TopicTestBase.MY_EFFECTIVE_TOPIC;
+import static org.onap.policy.common.message.bus.event.base.TopicTestBase.MY_PARTITION;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_HTTP_HTTPS_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_MANAGED_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SERVERS_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SINK_PARTITION_KEY_SUFFIX;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import lombok.Getter;
+import org.onap.policy.common.message.bus.event.base.TopicPropertyBuilder;
+import org.onap.policy.common.parameters.topic.TopicParameters;
+
+@Getter
+public class KafkaTopicPropertyBuilder extends TopicPropertyBuilder {
+
+    public static final String SERVER = "localhost:9092";
+    public static final String TOPIC2 = "my-topic-2";
+    public static final String ADDITIONAL_PROPS = "{\"security.protocol\": \"SASL_PLAINTEXT\","
+        + "\"sasl.mechanism\": \"SCRAM-SHA-512\",\"sasl.jaas.config\": "
+        + "\"org.apache.kafka.common.security.plain.PlainLoginModule "
+        + "required username=abc password=abc serviceName=kafka;\"}";
+
+    private final TopicParameters params = new TopicParameters();
+
+    /**
+     * Constructs the object.
+     *
+     * @param prefix the prefix for the properties to be built
+     */
+    public KafkaTopicPropertyBuilder(String prefix) {
+        super(prefix);
+    }
+
+    /**
+     * Adds a topic and configures it's properties with default values.
+     *
+     * @param topic the topic to be added
+     * @return this builder
+     */
+    public KafkaTopicPropertyBuilder makeTopic(String topic) {
+        addTopic(topic);
+
+        setTopicProperty(PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX, MY_EFFECTIVE_TOPIC);
+        setTopicProperty(PROPERTY_MANAGED_SUFFIX, "true");
+        setTopicProperty(PROPERTY_HTTP_HTTPS_SUFFIX, "true");
+        setTopicProperty(PROPERTY_TOPIC_SINK_PARTITION_KEY_SUFFIX, MY_PARTITION);
+        setTopicProperty(PROPERTY_TOPIC_SERVERS_SUFFIX, SERVER);
+        setTopicProperty(".additionalProps", ADDITIONAL_PROPS);
+
+        params.setTopicCommInfrastructure("kafka");
+        params.setTopic(topic);
+        params.setEffectiveTopic(MY_EFFECTIVE_TOPIC);
+        params.setManaged(true);
+        params.setUseHttps(true);
+        params.setPartitionId(MY_PARTITION);
+        params.setServers(List.of(SERVER));
+        params.setAdditionalProps(getAdditionalProps());
+
+        return this;
+    }
+
+    private Map<String, String> getAdditionalProps() {
+        try {
+            return new ObjectMapper().readValue(ADDITIONAL_PROPS, Map.class);
+        } catch (JsonProcessingException e) {
+            return Collections.emptyMap();
+        }
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkFactoryTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkFactoryTest.java
new file mode 100644
index 00000000..62210361
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkFactoryTest.java
@@ -0,0 +1,200 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2022, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_KAFKA_SINK_TOPICS;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX;
+
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Properties;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.base.TopicPropertyBuilder;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+class KafkaTopicSinkFactoryTest extends KafkaTopicFactoryTestBase<KafkaTopicSink> {
+
+    private SinkFactory factory;
+    public static final String KAFKA_SERVER = "localhost:9092";
+
+    /**
+     * Creates the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        factory = new SinkFactory();
+    }
+
+    @AfterEach
+    public void tearDown() {
+        factory.destroy();
+    }
+
+    @Test
+    @Override
+    public void testBuildBusTopicParams() {
+        super.testBuildBusTopicParams();
+        super.testBuildBusTopicParams_Ex();
+    }
+
+    @Test
+    @Override
+    public void testBuildListOfStringString() {
+        super.testBuildListOfStringString();
+
+        // check parameters that were used
+        BusTopicParams params = getLastParams();
+        assertFalse(params.isAllowSelfSignedCerts());
+    }
+
+    @Test
+    @Override
+    public void testBuildProperties() {
+        List<KafkaTopicSink> topics = buildTopics(makePropBuilder().makeTopic(MY_TOPIC).build());
+        assertEquals(1, topics.size());
+        assertEquals(MY_TOPIC, topics.get(0).getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, topics.get(0).getEffectiveTopic());
+
+        BusTopicParams params = getLastParams();
+        assertTrue(params.isManaged());
+        assertFalse(params.isUseHttps());
+        assertEquals(List.of(KAFKA_SERVER), params.getServers());
+        assertEquals(MY_TOPIC, params.getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, params.getEffectiveTopic());
+        assertEquals(MY_PARTITION, params.getPartitionId());
+        assertNotNull(params.getAdditionalProps());
+
+        List<KafkaTopicSink> topics2 = buildTopics(makePropBuilder().makeTopic(TOPIC3)
+            .removeTopicProperty(PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX).build());
+        assertEquals(1, topics2.size());
+        assertEquals(TOPIC3, topics2.get(0).getTopic());
+        assertEquals(topics2.get(0).getTopic(), topics2.get(0).getEffectiveTopic());
+
+        initFactory();
+
+        assertEquals(1, buildTopics(makePropBuilder().makeTopic(MY_TOPIC).build()).size());
+    }
+
+    @Test
+    void testBuildFromProperties() {
+        Properties props = makePropBuilder().makeTopic(MY_TOPIC).build();
+        var listTopic = factory.build(props);
+        assertNotNull(listTopic);
+    }
+
+    @Test
+    @Override
+    public void testDestroyString_testGet_testInventory() {
+        super.testDestroyString_testGet_testInventory();
+        super.testDestroyString_Ex();
+    }
+
+    @Test
+    @Override
+    public void testDestroy() {
+        super.testDestroy();
+    }
+
+    @Test
+    void testGet() {
+        super.testGet_Ex();
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(factory.toString().startsWith("IndexedKafkaTopicSinkFactory ["));
+    }
+
+    @Override
+    protected void initFactory() {
+        if (factory != null) {
+            factory.destroy();
+        }
+
+        factory = new SinkFactory();
+    }
+
+    @Override
+    protected List<KafkaTopicSink> buildTopics(Properties properties) {
+        return factory.build(properties);
+    }
+
+    @Override
+    protected KafkaTopicSink buildTopic(BusTopicParams params) {
+        return factory.build(params);
+    }
+
+    @Override
+    protected KafkaTopicSink buildTopic(List<String> servers, String topic) {
+        return factory.build(servers, topic);
+    }
+
+    @Override
+    protected void destroyFactory() {
+        factory.destroy();
+    }
+
+    @Override
+    protected void destroyTopic(String topic) {
+        factory.destroy(topic);
+    }
+
+    @Override
+    protected List<KafkaTopicSink> getInventory() {
+        return factory.inventory();
+    }
+
+    @Override
+    protected KafkaTopicSink getTopic(String topic) {
+        return factory.get(topic);
+    }
+
+    @Override
+    protected BusTopicParams getLastParams() {
+        return factory.params.getLast();
+    }
+
+    @Override
+    protected TopicPropertyBuilder makePropBuilder() {
+        return new KafkaTopicPropertyBuilder(PROPERTY_KAFKA_SINK_TOPICS);
+    }
+
+    /**
+     * Factory that records the parameters of all the sinks it creates.
+     */
+    private static class SinkFactory extends IndexedKafkaTopicSinkFactory {
+        private Deque<BusTopicParams> params = new LinkedList<>();
+
+        @Override
+        protected KafkaTopicSink makeSink(BusTopicParams busTopicParams) {
+            params.add(busTopicParams);
+            return super.makeSink(busTopicParams);
+        }
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkTest.java
new file mode 100644
index 00000000..8818a27f
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSinkTest.java
@@ -0,0 +1,34 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Engine - Common Modules
+ * ================================================================================
+ * Copyright (C) 2022, 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+
+class KafkaTopicSinkTest {
+
+    @Test
+    void test() {
+        assertNotNull(KafkaTopicFactories.getSinkFactory());
+    }
+
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceFactoryTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceFactoryTest.java
new file mode 100644
index 00000000..c91e548b
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceFactoryTest.java
@@ -0,0 +1,168 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Engine - Common Modules
+ * ================================================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_KAFKA_SOURCE_TOPICS;
+
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Properties;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.base.TopicPropertyBuilder;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+class KafkaTopicSourceFactoryTest extends KafkaTopicFactoryTestBase<KafkaTopicSource> {
+
+    private SourceFactory factory;
+
+    public static final String KAFKA_SERVER = "localhost:9092";
+
+    /**
+     * Creates the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        factory = new SourceFactory();
+    }
+
+    @AfterEach
+    public void tearDown() {
+        factory.destroy();
+    }
+
+    @Test
+    @Override
+    public void testBuildProperties() {
+
+        initFactory();
+
+        List<KafkaTopicSource> topics = buildTopics(makePropBuilder().makeTopic(MY_TOPIC).build());
+        assertEquals(1, topics.size());
+        assertEquals(MY_TOPIC, topics.get(0).getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, topics.get(0).getEffectiveTopic());
+
+        BusTopicParams params = getLastParams();
+        assertTrue(params.isManaged());
+        assertFalse(params.isUseHttps());
+        assertEquals(List.of(KAFKA_SERVER), params.getServers());
+        assertEquals(MY_TOPIC, params.getTopic());
+        assertEquals(MY_EFFECTIVE_TOPIC, params.getEffectiveTopic());
+    }
+
+    @Test
+    @Override
+    public void testDestroyString_testGet_testInventory() {
+        super.testDestroyString_testGet_testInventory();
+        super.testDestroyString_Ex();
+    }
+
+    @Test
+    @Override
+    public void testDestroy() {
+        super.testDestroy();
+    }
+
+    @Test
+    void testGet() {
+        super.testGet_Ex();
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(factory.toString().startsWith("IndexedKafkaTopicSourceFactory ["));
+    }
+
+    @Override
+    protected void initFactory() {
+        if (factory != null) {
+            factory.destroy();
+        }
+
+        factory = new SourceFactory();
+    }
+
+    @Override
+    protected List<KafkaTopicSource> buildTopics(Properties properties) {
+        return factory.build(properties);
+    }
+
+    @Override
+    protected KafkaTopicSource buildTopic(BusTopicParams params) {
+        return factory.build(params);
+    }
+
+    @Override
+    protected KafkaTopicSource buildTopic(List<String> servers, String topic) {
+        return factory.build(servers, topic);
+    }
+
+    @Override
+    protected void destroyFactory() {
+        factory.destroy();
+    }
+
+    @Override
+    protected void destroyTopic(String topic) {
+        factory.destroy(topic);
+    }
+
+    @Override
+    protected List<KafkaTopicSource> getInventory() {
+        return factory.inventory();
+    }
+
+    @Override
+    protected KafkaTopicSource getTopic(String topic) {
+        return factory.get(topic);
+    }
+
+    @Override
+    protected BusTopicParams getLastParams() {
+        return factory.params.getLast();
+    }
+
+    @Override
+    protected TopicPropertyBuilder makePropBuilder() {
+        return new KafkaTopicPropertyBuilder(PROPERTY_KAFKA_SOURCE_TOPICS);
+    }
+
+    /**
+     * Factory that records the parameters of all the sources it creates.
+     */
+    private static class SourceFactory extends IndexedKafkaTopicSourceFactory {
+        private final Deque<BusTopicParams> params = new LinkedList<>();
+
+        @Override
+        protected KafkaTopicSource makeSource(BusTopicParams busTopicParams) {
+            params.add(busTopicParams);
+            return super.makeSource(busTopicParams);
+        }
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceTest.java
new file mode 100644
index 00000000..5572bc01
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/KafkaTopicSourceTest.java
@@ -0,0 +1,34 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Engine - Common Modules
+ * ================================================================================
+ * Copyright (C) 2022-2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import org.junit.jupiter.api.Test;
+
+class KafkaTopicSourceTest {
+
+    @Test
+    void verifyKafkaTopicFactoriesNotNull() {
+        assertNotNull(KafkaTopicFactories.getSourceFactory());
+    }
+
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/SingleThreadedKafkaTopicSourceTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/SingleThreadedKafkaTopicSourceTest.java
new file mode 100644
index 00000000..0c732ba7
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/kafka/SingleThreadedKafkaTopicSourceTest.java
@@ -0,0 +1,61 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2018-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.kafka;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.base.TopicTestBase;
+
+class SingleThreadedKafkaTopicSourceTest extends TopicTestBase {
+    private SingleThreadedKafkaTopicSource source;
+
+    /**
+     * Creates the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+
+        source = new SingleThreadedKafkaTopicSource(makeKafkaBuilder().build());
+    }
+
+    @AfterEach
+    public void tearDown() {
+        source.shutdown();
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(source.toString().startsWith("SingleThreadedKafkaTopicSource ["));
+        source.shutdown();
+    }
+
+    @Test
+    void testGetTopicCommInfrastructure() {
+        assertEquals(CommInfrastructure.KAFKA, source.getTopicCommInfrastructure());
+    }
+
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicEndpointTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicEndpointTest.java
new file mode 100644
index 00000000..3ebec83c
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicEndpointTest.java
@@ -0,0 +1,121 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import java.util.Arrays;
+import java.util.Collections;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.TopicListener;
+import org.onap.policy.common.message.bus.event.base.TopicTestBase;
+
+public abstract class NoopTopicEndpointTest<F extends NoopTopicFactory<T>, T extends NoopTopicEndpoint>
+    extends TopicTestBase {
+
+    protected final F factory;
+    protected T endpoint;
+
+    public NoopTopicEndpointTest(F factory) {
+        this.factory = factory;
+    }
+
+    protected abstract boolean io(String message);
+
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+        this.endpoint = this.factory.build(servers, MY_TOPIC);
+    }
+
+    @Test
+    void testIo() {
+        TopicListener listener = mock(TopicListener.class);
+        this.endpoint.register(listener);
+        this.endpoint.start();
+
+        assertTrue(io(MY_MESSAGE));
+        assertSame(MY_MESSAGE, this.endpoint.getRecentEvents()[0]);
+        assertEquals(Collections.singletonList(MY_MESSAGE), Arrays.asList(this.endpoint.getRecentEvents()));
+        verify(listener).onTopicEvent(CommInfrastructure.NOOP, MY_TOPIC, MY_MESSAGE);
+
+        this.endpoint.unregister(listener);
+    }
+
+    @Test
+    void testIoNullMessage() {
+        assertThatThrownBy(() -> io(null)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testIoEmptyMessage() {
+        assertThatThrownBy(() -> io("")).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testOfferNotStarted() {
+        assertThatThrownBy(() -> io(MY_MESSAGE)).isInstanceOf(IllegalStateException.class);
+    }
+
+    @Test
+    void testGetTopicCommInfrastructure() {
+        assertEquals(CommInfrastructure.NOOP, this.endpoint.getTopicCommInfrastructure());
+    }
+
+    @Test
+    void testStart_testStop_testShutdown() {
+        this.endpoint.start();
+        assertTrue(this.endpoint.isAlive());
+
+        // start again
+        this.endpoint.start();
+        assertTrue(this.endpoint.isAlive());
+
+        // stop
+        this.endpoint.stop();
+        assertFalse(this.endpoint.isAlive());
+
+        // re-start again
+        this.endpoint.start();
+        assertTrue(this.endpoint.isAlive());
+
+        // shutdown
+        this.endpoint.shutdown();
+        assertFalse(this.endpoint.isAlive());
+    }
+
+    @Test
+    void testStart_Locked() {
+        this.endpoint.lock();
+        assertThatThrownBy(() -> this.endpoint.start()).isInstanceOf(IllegalStateException.class);
+    }
+
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactoryTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactoryTest.java
new file mode 100644
index 00000000..4dcba86e
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicFactoryTest.java
@@ -0,0 +1,257 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019-2020 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_MANAGED_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SERVERS_SUFFIX;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Properties;
+import org.apache.commons.lang3.RandomStringUtils;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.event.base.TopicFactoryTestBase;
+import org.onap.policy.common.message.bus.event.base.TopicPropertyBuilder;
+import org.onap.policy.common.message.bus.event.base.TopicTestBase;
+import org.onap.policy.common.parameters.topic.BusTopicParams;
+
+public abstract class NoopTopicFactoryTest<F extends NoopTopicFactory<T>, T extends NoopTopicEndpoint>
+    extends TopicFactoryTestBase<T> {
+
+    private static final List<String> NOOP_SERVERS = List.of(CommInfrastructure.NOOP.toString());
+    private F factory = null;
+
+    protected abstract F buildFactory();
+
+    /**
+     * Creates the object to be tested.
+     */
+    @BeforeEach
+    @Override
+    public void setUp() {
+        super.setUp();
+        initFactory();
+    }
+
+    @AfterEach
+    void tearDown() {
+        factory.destroy();
+    }
+
+    @Test
+    void testBuildBusTopicParams() {
+        initFactory();
+
+        T item1 = buildTopic(makeParams(servers));
+        assertNotNull(item1);
+
+        assertEquals(servers, item1.getServers());
+        assertEquals(MY_TOPIC, item1.getTopic());
+    }
+
+    @Test
+    void testBuildListOfStringStringBoolean() {
+        initFactory();
+
+        T item1 = buildTopic(servers, MY_TOPIC, true);
+        assertNotNull(item1);
+
+        assertEquals(servers, item1.getServers());
+        assertEquals(MY_TOPIC, item1.getTopic());
+
+        // managed topic - should not build a new one
+        assertEquals(item1, buildTopic(servers, MY_TOPIC, true));
+
+        T item2 = buildTopic(servers, TOPIC2, true);
+        assertNotNull(item2);
+        assertNotSame(item1, item2);
+
+        // duplicate - should be the same, as these topics are managed
+        List<String> randomServers = new ArrayList<>();
+        randomServers.add(RandomStringUtils.randomAlphanumeric(8));
+        T item3 = buildTopic(randomServers, TOPIC2, true);
+        assertSame(item2, item3);
+
+        T item4 = buildTopic(Collections.emptyList(), TOPIC2, true);
+        assertSame(item3, item4);
+
+        // null server list
+        initFactory();
+        assertEquals(NOOP_SERVERS, buildTopic(null, MY_TOPIC, true).getServers());
+
+        // empty server list
+        initFactory();
+        assertEquals(NOOP_SERVERS, buildTopic(Collections.emptyList(), MY_TOPIC, true).getServers());
+
+        // unmanaged topic
+        initFactory();
+        item1 = buildTopic(servers, MY_TOPIC, false);
+        assertNotSame(item1, buildTopic(servers, MY_TOPIC, false));
+    }
+
+    @Test
+    void testBuildListOfStringStringBoolean_NullTopic() {
+        assertThatThrownBy(() -> buildTopic(servers, null, true)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testBuildListOfStringStringBoolean_EmptyTopic() {
+        assertThatThrownBy(() -> buildTopic(servers, "", true)).isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void testBuildProperties() {
+        // managed topic
+        initFactory();
+        assertEquals(1, buildTopics(makePropBuilder().makeTopic(MY_TOPIC).build()).size());
+        assertNotNull(factory.get(MY_TOPIC));
+
+        // unmanaged topic - get() will throw an exception
+        initFactory();
+        assertEquals(1, buildTopics(makePropBuilder().makeTopic(MY_TOPIC)
+                        .setTopicProperty(PROPERTY_MANAGED_SUFFIX, "false").build()).size());
+        assertThatIllegalStateException().isThrownBy(() -> factory.get(MY_TOPIC));
+
+        // managed undefined - default to true
+        initFactory();
+        assertEquals(1, buildTopics(
+                        makePropBuilder().makeTopic(MY_TOPIC).removeTopicProperty(PROPERTY_MANAGED_SUFFIX).build())
+                                        .size());
+        assertNotNull(factory.get(MY_TOPIC));
+
+        // managed empty - default to true
+        initFactory();
+        assertEquals(1, buildTopics(
+                        makePropBuilder().makeTopic(MY_TOPIC).setTopicProperty(PROPERTY_MANAGED_SUFFIX, "").build())
+                                        .size());
+        assertNotNull(factory.get(MY_TOPIC));
+
+        initFactory();
+
+        // null topic list
+        assertTrue(buildTopics(makePropBuilder().build()).isEmpty());
+
+        // empty topic list
+        assertTrue(buildTopics(makePropBuilder().addTopic("").build()).isEmpty());
+
+        // null server list
+        initFactory();
+        T endpoint = buildTopics(makePropBuilder().makeTopic(MY_TOPIC)
+                        .removeTopicProperty(PROPERTY_TOPIC_SERVERS_SUFFIX).build()).get(0);
+        assertEquals(NOOP_SERVERS, endpoint.getServers());
+
+        // empty server list
+        initFactory();
+        endpoint = buildTopics(makePropBuilder().makeTopic(MY_TOPIC).setTopicProperty(PROPERTY_TOPIC_SERVERS_SUFFIX, "")
+                        .build()).get(0);
+        assertEquals(NOOP_SERVERS, endpoint.getServers());
+
+        // test other options
+        super.testBuildProperties_Multiple();
+    }
+
+    @Test
+    @Override
+    public void testDestroyString_testGet_testInventory() {
+        super.testDestroyString_testGet_testInventory();
+        super.testDestroyString_Ex();
+    }
+
+    @Test
+    @Override
+    public void testDestroy() {
+        super.testDestroy();
+    }
+
+    @Test
+    void testGet() {
+        super.testGet_Ex();
+    }
+
+    @Override
+    protected void initFactory() {
+        if (factory != null) {
+            factory.destroy();
+        }
+
+        factory = buildFactory();
+    }
+
+    @Override
+    protected List<T> buildTopics(Properties properties) {
+        return factory.build(properties);
+    }
+
+    protected T buildTopic(BusTopicParams param) {
+        return factory.build(param);
+    }
+
+    protected T buildTopic(List<String> servers, String topic, boolean managed) {
+        return factory.build(servers, topic, managed);
+    }
+
+    @Override
+    protected void destroyFactory() {
+        factory.destroy();
+    }
+
+    @Override
+    protected void destroyTopic(String topic) {
+        factory.destroy(topic);
+    }
+
+    @Override
+    protected List<T> getInventory() {
+        return factory.inventory();
+    }
+
+    @Override
+    protected T getTopic(String topic) {
+        return factory.get(topic);
+    }
+
+    @Override
+    protected TopicPropertyBuilder makePropBuilder() {
+        return new NoopTopicPropertyBuilder(factory.getTopicsPropertyName());
+    }
+
+    private BusTopicParams makeParams(List<String> servers) {
+        BusTopicParams params = new BusTopicParams();
+
+        params.setServers(servers);
+        params.setTopic(TopicTestBase.MY_TOPIC);
+        params.setManaged(true);
+
+        return params;
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicPropertyBuilder.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicPropertyBuilder.java
new file mode 100644
index 00000000..57b78435
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicPropertyBuilder.java
@@ -0,0 +1,77 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2018-2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.onap.policy.common.message.bus.event.base.TopicTestBase.MY_EFFECTIVE_TOPIC;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_ALLOW_SELF_SIGNED_CERTIFICATES_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_HTTP_HTTPS_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_MANAGED_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX;
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_TOPIC_SERVERS_SUFFIX;
+
+import java.util.List;
+import lombok.Getter;
+import org.onap.policy.common.message.bus.event.base.TopicPropertyBuilder;
+import org.onap.policy.common.parameters.topic.TopicParameters;
+
+@Getter
+public class NoopTopicPropertyBuilder extends TopicPropertyBuilder {
+
+    public static final String SERVER = "my-server";
+
+    private final TopicParameters params = new TopicParameters();
+
+    /**
+     * Constructs the object.
+     *
+     * @param prefix the prefix for the properties to be built
+     */
+    public NoopTopicPropertyBuilder(String prefix) {
+        super(prefix);
+    }
+
+    /**
+     * Adds a topic and configures it's properties with default values.
+     *
+     * @param topic the topic to be added
+     * @return this builder
+     */
+    public NoopTopicPropertyBuilder makeTopic(String topic) {
+        addTopic(topic);
+
+        setTopicProperty(PROPERTY_TOPIC_EFFECTIVE_TOPIC_SUFFIX, MY_EFFECTIVE_TOPIC);
+        setTopicProperty(PROPERTY_MANAGED_SUFFIX, "true");
+        setTopicProperty(PROPERTY_HTTP_HTTPS_SUFFIX, "true");
+        setTopicProperty(PROPERTY_ALLOW_SELF_SIGNED_CERTIFICATES_SUFFIX, "true");
+        setTopicProperty(PROPERTY_TOPIC_SERVERS_SUFFIX, SERVER);
+
+        params.setTopicCommInfrastructure("noop");
+        params.setTopic(topic);
+        params.setEffectiveTopic(MY_EFFECTIVE_TOPIC);
+        params.setManaged(true);
+        params.setUseHttps(true);
+        params.setAllowSelfSignedCerts(true);
+        params.setServers(List.of(SERVER));
+
+        return this;
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkFactoryTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkFactoryTest.java
new file mode 100644
index 00000000..ecd4df1e
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkFactoryTest.java
@@ -0,0 +1,39 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2018-2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class NoopTopicSinkFactoryTest extends NoopTopicFactoryTest<NoopTopicSinkFactory, NoopTopicSink> {
+
+    @Override
+    protected NoopTopicSinkFactory buildFactory() {
+        return new NoopTopicSinkFactory();
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(new NoopTopicSinkFactory().toString().startsWith("NoopTopicSinkFactory ["));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkTest.java
new file mode 100644
index 00000000..ecba379f
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSinkTest.java
@@ -0,0 +1,58 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import org.junit.jupiter.api.Test;
+
+class NoopTopicSinkTest extends NoopTopicEndpointTest<NoopTopicSinkFactory, NoopTopicSink> {
+
+    public NoopTopicSinkTest() {
+        super(new NoopTopicSinkFactory());
+    }
+
+    @Override
+    protected boolean io(String message) {
+        return endpoint.send(message);
+    }
+
+    @Test
+    void testToString() {
+        assertThat(endpoint.toString()).startsWith("NoopTopicSink");
+    }
+
+    @Test
+    void testSend() {
+        NoopTopicSink sink = new NoopTopicSink(servers, MY_TOPIC) {
+            @Override
+            protected boolean broadcast(String message) {
+                throw new RuntimeException(EXPECTED);
+            }
+
+        };
+
+        sink.start();
+        assertFalse(sink.send(MY_MESSAGE));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceFactoryTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceFactoryTest.java
new file mode 100644
index 00000000..c9038068
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceFactoryTest.java
@@ -0,0 +1,39 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class NoopTopicSourceFactoryTest extends NoopTopicFactoryTest<NoopTopicSourceFactory, NoopTopicSource>   {
+
+    @Override
+    protected NoopTopicSourceFactory buildFactory() {
+        return new NoopTopicSourceFactory();
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(new NoopTopicSourceFactory().toString().startsWith("NoopTopicSourceFactory ["));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceTest.java
new file mode 100644
index 00000000..51ff109b
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/event/noop/NoopTopicSourceTest.java
@@ -0,0 +1,56 @@
+/*
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.event.noop;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class NoopTopicSourceTest extends NoopTopicEndpointTest<NoopTopicSourceFactory, NoopTopicSource> {
+
+    public NoopTopicSourceTest() {
+        super(new NoopTopicSourceFactory());
+    }
+
+    @Override
+    protected boolean io(String message) {
+        return this.endpoint.offer(message);
+    }
+
+    @Test
+    void testToString() {
+        assertTrue(this.endpoint.toString().startsWith("NoopTopicSource"));
+    }
+
+    @Test
+    void testOffer() {
+        NoopTopicSource source = new NoopTopicSource(servers, MY_TOPIC) {
+            @Override
+            protected boolean broadcast(String message) {
+                throw new RuntimeException(EXPECTED);
+            }
+
+        };
+
+        source.start();
+        assertFalse(source.offer(MY_MESSAGE));
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureApiTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureApiTest.java
new file mode 100644
index 00000000..776c5d57
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/features/NetLoggerFeatureApiTest.java
@@ -0,0 +1,86 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.features;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+import org.slf4j.Logger;
+
+@ExtendWith(MockitoExtension.class)
+class NetLoggerFeatureApiTest {
+
+    @Mock
+    private Logger mockLogger;
+
+    @Mock
+    private EventType mockEventType;
+
+    @Mock
+    private CommInfrastructure mockCommInfrastructure;
+
+    private NetLoggerFeatureApi featureApi;
+
+    @BeforeEach
+    public void setUp() {
+        featureApi = new NetLoggerFeatureApi() {
+            @Override
+            public boolean beforeLog(Logger eventLogger, EventType type, CommInfrastructure protocol, String topic,
+                                     String message) {
+                return NetLoggerFeatureApi.super.beforeLog(eventLogger, type, protocol, topic, message);
+            }
+
+            @Override
+            public boolean afterLog(Logger eventLogger, EventType type, CommInfrastructure protocol, String topic,
+                                    String message) {
+                return NetLoggerFeatureApi.super.afterLog(eventLogger, type, protocol, topic, message);
+            }
+
+            @Override
+            public int getSequenceNumber() {
+                return 0;
+            }
+
+            @Override
+            public String getName() {
+                return NetLoggerFeatureApi.super.getName();
+            }
+        };
+    }
+
+    @Test
+    void testBeforeLogDefaultBehavior() {
+        boolean result = featureApi.beforeLog(mockLogger, mockEventType, mockCommInfrastructure,
+            "testTopic", "testMessage");
+        assertFalse(result, "Expected beforeLog to return false by default");
+    }
+
+    @Test
+    void testAfterLogDefaultBehavior() {
+        boolean result = featureApi.afterLog(mockLogger, mockEventType, mockCommInfrastructure,
+            "testTopic", "testMessage");
+        assertFalse(result, "Expected afterLog to return false by default");
+    }
+}
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/utils/KafkaPropertyUtilsTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/utils/KafkaPropertyUtilsTest.java
new file mode 100644
index 00000000..55f6a69f
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/utils/KafkaPropertyUtilsTest.java
@@ -0,0 +1,54 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2024 Nordix Foundation.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.utils;
+
+import static org.onap.policy.common.message.bus.properties.MessageBusProperties.PROPERTY_ADDITIONAL_PROPS_SUFFIX;
+
+import java.util.Properties;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.utils.properties.PropertyUtils;
+
+class KafkaPropertyUtilsTest {
+
+    @Test
+    void test() {
+        var properties = new Properties();
+        properties.setProperty("mytopic" + PROPERTY_ADDITIONAL_PROPS_SUFFIX, "{444-");
+        PropertyUtils props = new PropertyUtils(properties, "mytopic", null);
+
+        var build = KafkaPropertyUtils.makeBuilder(props, "mytopic", "servers").build();
+        Assertions.assertTrue(build.getAdditionalProps().isEmpty());
+
+        properties.setProperty("mytopic" + PROPERTY_ADDITIONAL_PROPS_SUFFIX,
+            "{\"security.protocol\": \"SASL_PLAINTEXT\"}");
+        build = KafkaPropertyUtils.makeBuilder(props, "mytopic", "servers").build();
+        Assertions.assertTrue(build.getAdditionalProps().containsKey("security.protocol"));
+
+        properties.setProperty("mytopic" + PROPERTY_ADDITIONAL_PROPS_SUFFIX,
+            "{\"security.protocol\": false }");
+        build = KafkaPropertyUtils.makeBuilder(props, "mytopic", "servers").build();
+        Assertions.assertTrue(build.getAdditionalProps().isEmpty());
+
+        properties.setProperty("mytopic" + PROPERTY_ADDITIONAL_PROPS_SUFFIX, "");
+        build = KafkaPropertyUtils.makeBuilder(props, "mytopic", "servers").build();
+        Assertions.assertTrue(build.getAdditionalProps().isEmpty());
+    }
+  
+}
\ No newline at end of file
diff --git a/message-bus/src/test/java/org/onap/policy/common/message/bus/utils/NetLoggerUtilTest.java b/message-bus/src/test/java/org/onap/policy/common/message/bus/utils/NetLoggerUtilTest.java
new file mode 100644
index 00000000..df621f5b
--- /dev/null
+++ b/message-bus/src/test/java/org/onap/policy/common/message/bus/utils/NetLoggerUtilTest.java
@@ -0,0 +1,269 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Modifications Copyright (C) 2024 Nordix Foundation
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.message.bus.utils;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.AppenderBase;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onap.policy.common.message.bus.event.Topic.CommInfrastructure;
+import org.onap.policy.common.message.bus.features.NetLoggerFeatureApi;
+import org.onap.policy.common.message.bus.features.NetLoggerFeatureProviders;
+import org.onap.policy.common.message.bus.utils.NetLoggerUtil.EventType;
+import org.slf4j.Logger;
+
+/**
+ * Test class for network log utilities such as logging and feature invocation.
+ */
+class NetLoggerUtilTest {
+
+    private static final String TEST_TOPIC = "test-topic";
+    private static final String MESSAGE = "hello world!";
+    /**
+     * Test feature used for junits.
+     */
+    private static NetLoggerFeature netLoggerFeature;
+
+    /**
+     * Obtains the test implementation of NetLoggerFeatureApi.
+     */
+    @BeforeAll
+    public static void setUp() {
+        netLoggerFeature = (NetLoggerFeature) NetLoggerFeatureProviders.getProviders().getList().get(0);
+    }
+
+    /**
+     * Clears events list and resets return/exceptions flags before invoking every unit test.
+     */
+    @BeforeEach
+    public void reset() {
+        TestAppender.clear();
+        netLoggerFeature.setReturnValue(false, false);
+        netLoggerFeature.setExceptions(false, false);
+    }
+
+    /**
+     * Tests obtaining the network logger instance.
+     */
+    @Test
+    void getNetworkLoggerTest() {
+        assertEquals("network", NetLoggerUtil.getNetworkLogger().getName());
+    }
+
+    /**
+     * Tests logging a message to the network logger and invoking features before/after logging.
+     */
+    @Test
+    void logTest() {
+        NetLoggerUtil.log(EventType.IN, CommInfrastructure.NOOP, TEST_TOPIC, MESSAGE);
+        assertEquals(3, TestAppender.events.size());
+    }
+
+    /**
+     * Tests that the network logger is used to log messages if a logger is not passed in.
+     */
+    @Test
+    void logDefaultTest() {
+        NetLoggerUtil.log(null, EventType.IN, CommInfrastructure.NOOP, TEST_TOPIC, MESSAGE);
+        assertEquals(3, TestAppender.events.size());
+        assertEquals("network", TestAppender.events.get(0).getLoggerName());
+    }
+
+    /**
+     * Tests a NetLoggerFeature that replaces base implementation before logging.
+     */
+    @Test
+    void beforeLogReturnTrueTest() {
+        netLoggerFeature.setReturnValue(true, false);
+        NetLoggerUtil.log(null, EventType.IN, CommInfrastructure.NOOP, TEST_TOPIC, MESSAGE);
+        assertEquals(1, TestAppender.events.size());
+    }
+
+    /**
+     * Tests a NetLoggerFeature that post processes a logged message.
+     */
+    @Test
+    void afterLogReturnTrueTest() {
+        netLoggerFeature.setReturnValue(false, true);
+        NetLoggerUtil.log(null, EventType.IN, CommInfrastructure.NOOP, TEST_TOPIC, MESSAGE);
+        assertEquals(3, TestAppender.events.size());
+    }
+
+    /**
+     * Tests throwing an exception in the before hook.
+     */
+    @Test
+    void beforeLogExceptionTest() {
+        netLoggerFeature.setExceptions(true, false);
+        NetLoggerUtil.log(null, EventType.IN, CommInfrastructure.NOOP, TEST_TOPIC, MESSAGE);
+        assertEquals(2, TestAppender.events.size());
+    }
+
+    /**
+     * Tests throwing an exception in the after hook.
+     */
+    @Test
+    void afterLogExceptionTest() {
+        netLoggerFeature.setExceptions(false, true);
+        NetLoggerUtil.log(null, EventType.IN, CommInfrastructure.NOOP, TEST_TOPIC, MESSAGE);
+        assertEquals(2, TestAppender.events.size());
+    }
+
+    /**
+     * A custom list appender to track messages being logged to the network logger.
+     * NOTE: Check src/test/resources/logback-test.xml for network logger configurations.
+     */
+    public static class TestAppender extends AppenderBase<ILoggingEvent> {
+
+        /**
+         * List of logged events.
+         */
+        private static final List<ILoggingEvent> events = new ArrayList<>();
+
+        /**
+         * Called after every unit test to clear list of events.
+         */
+        public static void clear() {
+            events.clear();
+        }
+
+        /**
+         * Appends each event to the event list.
+         */
+        @Override
+        protected void append(ILoggingEvent event) {
+            events.add(event);
+        }
+
+    }
+
+    /**
+     * Test implementation of NetLoggerFeatureApi to be used by junits.
+     */
+    public static class NetLoggerFeature implements NetLoggerFeatureApi {
+
+        /**
+         * Used for setting the return values of before/after hooks.
+         */
+        private boolean beforeReturn = false;
+        private boolean afterReturn = false;
+
+        /**
+         * Used for throwing an exception in the before/after hooks.
+         */
+        private boolean beforeException = false;
+        private boolean afterException = false;
+
+
+        /**
+         * Gets sequence number.
+         */
+        @Override
+        public int getSequenceNumber() {
+            return 0;
+        }
+
+        /**
+         * Get beforeLog return value.
+         */
+        public boolean getBeforeReturn() {
+            return this.beforeReturn;
+        }
+
+        /**
+         * Get afterLog return value.
+         */
+        public boolean getAfterReturn() {
+            return this.afterReturn;
+        }
+
+        /**
+         * Sets the return value for the before/after hooks.
+         *
+         * @param beforeVal beforeLog() return value
+         * @param afterVal  afterLog() return value
+         */
+        public void setReturnValue(boolean beforeVal, boolean afterVal) {
+            this.beforeReturn = beforeVal;
+            this.afterReturn = afterVal;
+        }
+
+        /**
+         * Gets beforeException boolean.
+         */
+        public boolean getBeforeException() {
+            return this.beforeException;
+        }
+
+        /**
+         * Gets afterException boolean.
+         */
+        public boolean getAfterException() {
+            return this.afterException;
+        }
+
+        /**
+         * Sets before/after flags to determine if the feature should throw an exception.
+         */
+        public void setExceptions(boolean beforeException, boolean afterException) {
+            this.beforeException = beforeException;
+            this.afterException = afterException;
+        }
+
+        /**
+         * Simple beforeLog message.
+         */
+        @Override
+        public boolean beforeLog(Logger eventLogger, EventType type, CommInfrastructure protocol, String topic,
+                                 String message) {
+
+            if (beforeException) {
+                throw new RuntimeException("beforeLog exception");
+            }
+
+            eventLogger.info("before feature test");
+
+            return this.beforeReturn;
+        }
+
+        /**
+         * Simple afterLog message.
+         */
+        @Override
+        public boolean afterLog(Logger eventLogger, EventType type, CommInfrastructure protocol, String topic,
+                                String message) {
+
+            if (afterException) {
+                throw new RuntimeException("afterLog exception");
+            }
+
+            eventLogger.info("after feature test");
+
+            return this.afterReturn;
+        }
+
+    }
+
+}
diff --git a/message-bus/src/test/resources/META-INF/services/org.onap.policy.common.message.bus.features.NetLoggerFeatureApi b/message-bus/src/test/resources/META-INF/services/org.onap.policy.common.message.bus.features.NetLoggerFeatureApi
new file mode 100644
index 00000000..7889cb8f
--- /dev/null
+++ b/message-bus/src/test/resources/META-INF/services/org.onap.policy.common.message.bus.features.NetLoggerFeatureApi
@@ -0,0 +1 @@
+org.onap.policy.common.message.bus.utils.NetLoggerUtilTest$NetLoggerFeature
\ No newline at end of file
diff --git a/message-bus/src/test/resources/logback-test.xml b/message-bus/src/test/resources/logback-test.xml
new file mode 100644
index 00000000..ddf4f8bb
--- /dev/null
+++ b/message-bus/src/test/resources/logback-test.xml
@@ -0,0 +1,42 @@
+<!--
+  ============LICENSE_START=======================================================
+  ONAP
+  ================================================================================
+  Copyright (C) 2024 Nordix Foundation.
+  ================================================================================
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  ============LICENSE_END=========================================================
+  -->
+<configuration>
+
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
+            <Pattern>
+                %d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36}.%M\(%line\) - %msg%n
+            </Pattern>
+        </encoder>
+    </appender>
+
+    <appender name="testAppender" class="org.onap.policy.common.message.bus.utils.NetLoggerUtilTest$TestAppender"/>
+
+    <logger name="org.onap.policy.drools.http.server.test" level="INFO"/>
+
+    <logger name="network" level="INFO">
+        <appender-ref ref="testAppender"/>
+    </logger>
+
+    <root level="WARN">
+        <appender-ref ref="STDOUT"/>
+    </root>
+
+</configuration>
\ No newline at end of file
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/TopicEndpointProxyTest.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/TopicEndpointProxyTest.json
new file mode 100644
index 00000000..5b2e712a
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/TopicEndpointProxyTest.json
@@ -0,0 +1,30 @@
+{
+  "locked": false,
+  "alive": false,
+  "topicSources": [
+    {
+      "servers": [
+        "my-server"
+      ],
+      "topic": "noop-source",
+      "effectiveTopic": "noop-source",
+      "recentEvents": [],
+      "alive": false,
+      "locked": false,
+      "topicCommInfrastructure": "NOOP"
+    }
+  ],
+  "topicSinks": [
+    {
+      "servers": [
+        "my-server"
+      ],
+      "topic": "noop-sink",
+      "effectiveTopic": "noop-sink",
+      "recentEvents": [],
+      "alive": false,
+      "locked": false,
+      "topicCommInfrastructure": "NOOP"
+    }
+  ]
+}
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/BusTopicBaseTest.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/BusTopicBaseTest.json
new file mode 100644
index 00000000..462278a4
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/BusTopicBaseTest.json
@@ -0,0 +1,14 @@
+{
+  "servers" : [ "svra", "svrb" ],
+  "topic" : "my-topic",
+  "effectiveTopic" : "my-effective-topic",
+  "recentEvents" : [ ],
+  "alive" : false,
+  "locked" : false,
+  "apiKey" : "my-api-key",
+  "apiSecret" : "my-api-secret",
+  "useHttps" : true,
+  "allowTracing": true,
+  "allowSelfSignedCerts" : true,
+  "topicCommInfrastructure" : "NOOP"
+}
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/InlineBusTopicSinkTest.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/InlineBusTopicSinkTest.json
new file mode 100644
index 00000000..1f2fb55f
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/InlineBusTopicSinkTest.json
@@ -0,0 +1,15 @@
+{
+  "servers" : [ "svra", "svrb" ],
+  "topic" : "my-topic",
+  "effectiveTopic" : "my-effective-topic",
+  "recentEvents" : [ ],
+  "alive" : false,
+  "locked" : false,
+  "apiKey" : "my-api-key",
+  "apiSecret" : "my-api-secret",
+  "useHttps" : true,
+  "allowTracing": true,
+  "allowSelfSignedCerts" : true,
+  "topicCommInfrastructure" : "NOOP",
+  "partitionKey" : "my-partition"
+}
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSourceTest.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSourceTest.json
new file mode 100644
index 00000000..305620c8
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/SingleThreadedBusTopicSourceTest.json
@@ -0,0 +1,18 @@
+{
+  "servers" : [ "svra", "svrb" ],
+  "topic" : "my-topic",
+  "effectiveTopic" : "my-effective-topic",
+  "recentEvents" : [ ],
+  "alive" : false,
+  "locked" : false,
+  "apiKey" : "my-api-key",
+  "apiSecret" : "my-api-secret",
+  "useHttps" : true,
+  "allowTracing": true,
+  "allowSelfSignedCerts" : true,
+  "consumerGroup" : "my-cons-group",
+  "consumerInstance" : "my-cons-inst",
+  "fetchTimeout" : 101,
+  "fetchLimit" : 100,
+  "topicCommInfrastructure" : "NOOP"
+}
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/TopicBaseTest.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/TopicBaseTest.json
new file mode 100644
index 00000000..b72b4efd
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/event/base/TopicBaseTest.json
@@ -0,0 +1,9 @@
+{
+  "servers" : [ "svra", "svrb" ],
+  "topic" : "my-topic",
+  "effectiveTopic" : "my-topic",
+  "recentEvents" : [ ],
+  "alive" : false,
+  "locked" : false,
+  "topicCommInfrastructure" : "NOOP"
+}
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_all_params.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_all_params.json
new file mode 100644
index 00000000..89e464dd
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_all_params.json
@@ -0,0 +1,62 @@
+{
+    "topicSources" : [ {
+        "topic" : "policy-pdp-pap1",
+        "servers" : [ "kafka2, kafka3" ],
+        "topicCommInfrastructure" : "kafka",
+        "effectiveTopic" : "my-effective-topic",
+        "apiKey" : "my-api-key",
+        "apiSecret" : "my-api-secret",
+        "port": 123,
+        "useHttps" : true,
+        "allowTracing": true,
+        "allowSelfSignedCerts" : true,
+        "consumerGroup" : "consumer group",
+        "consumerInstance" : "consumer instance",
+        "fetchTimeout" : 15000,
+        "fetchLimit" : 100,
+        "userName": "username",
+        "password": "password",
+        "managed": true,
+        "environment": "environment1",
+        "aftEnvironment": "aftEnvironment1",
+        "partner": "partner1",
+        "latitude": "1234",
+        "longitude": "1234",
+        "partitionId": "partition_id",
+        "additionalProps": {"xyz":"xyz"},
+        "clientName": "clientName1",
+        "hostname": "hostname1",
+        "basePath": "basePath1",
+        "serializationProvider": "serializationProvider1"
+    }],
+    "topicSinks" : [ {
+        "topic" : "policy-pdp-pap1",
+        "servers" : [ "kafka2, kafka3" ],
+        "topicCommInfrastructure" : "kafka",
+        "effectiveTopic" : "my-effective-topic",
+        "apiKey" : "my-api-key",
+        "apiSecret" : "my-api-secret",
+        "port": 123,
+        "useHttps" : true,
+        "allowTracing": true,
+        "allowSelfSignedCerts" : true,
+        "consumerGroup" : "consumer group",
+        "consumerInstance" : "consumer instance",
+        "fetchTimeout" : 15000,
+        "fetchLimit" : 100,
+        "userName": "username",
+        "password": "password",
+        "managed": true,
+        "environment": "environment1",
+        "aftEnvironment": "aftEnvironment1",
+        "partner": "partner1",
+        "latitude": "1234",
+        "longitude": "1234",
+        "partitionId": "partition_id",
+        "additionalProps": {"xyz":"xyz"},
+        "clientName": "clientName1",
+        "hostname": "hostname1",
+        "basePath": "basePath1",
+        "serializationProvider": "serializationProvider1"
+    }]
+}
\ No newline at end of file
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_invalid.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_invalid.json
new file mode 100644
index 00000000..775b4886
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_invalid.json
@@ -0,0 +1,6 @@
+{
+    "topicSources" : [{
+        "topic" : "ueb-source",
+        "servers" : ["my-server"]
+    }]
+}
\ No newline at end of file
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_missing_mandatory.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_missing_mandatory.json
new file mode 100644
index 00000000..216c11ec
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_missing_mandatory.json
@@ -0,0 +1,12 @@
+{
+    "topicSources" : [ {
+        "topic" : "policy-pdp-pap1",
+        "servers" : [],
+        "topicCommInfrastructure" : "kafka"
+    }],
+    "topicSinks" : [ {
+        "topic" : "policy-pdp-pap2",
+        "servers" : [ "kafka1, kafka2" ],
+        "topicCommInfrastructure" : "kafka"
+    }]
+}
\ No newline at end of file
diff --git a/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_valid.json b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_valid.json
new file mode 100644
index 00000000..2603bfdc
--- /dev/null
+++ b/message-bus/src/test/resources/org/onap/policy/common/message/bus/parameters/TopicParameters_valid.json
@@ -0,0 +1,30 @@
+{
+    "topicSources" : [ {
+        "topic" : "ueb-source",
+        "servers" : [ "my-server" ],
+        "topicCommInfrastructure" : "ueb"
+    },{
+        "topic" : "policy-pdp-pap1",
+        "servers" : [ "kafka1, kafka2" ],
+        "topicCommInfrastructure" : "kafka"
+    },{
+        "topic" : "policy-pdp-pap2",
+        "servers" : [ "kafka2, kafka3" ],
+        "topicCommInfrastructure" : "kafka"
+    }],
+    "topicSinks" : [ {
+        "topic" : "ueb-sink",
+        "servers" : [ "my-server" ],
+        "topicCommInfrastructure" : "ueb"
+    },{
+        "topic" : "policy-pdp-pap2",
+        "servers" : [ "kafka1, kafka2" ],
+        "topicCommInfrastructure" : "kafka"
+    },{
+        "topic" : "policy-pdp-pap3",
+        "servers" : [ "kafka2, kafka3" ],
+        "topicCommInfrastructure" : "kafka",
+        "effectiveTopic":"effectiveTopic1",
+        "allowSelfSignedCerts":true
+    }]
+}
\ No newline at end of file