Flesh out DMaaP simulator

Fleshed out the dmaap simulator with additional media types.
Added more junit tests.
Added buildDmaapSim() to simulators Util.

Change-Id: I39acd3df8e8d0ded21228e56fa1ef919cafc3772
Issue-ID: POLICY-2144
Signed-off-by: Jim Hahn <jrh3@att.com>

15 files changed, 778 insertions, 435 deletions

diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/DmaapSimConstants.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/DmaapSimConstants.java
deleted file mode 100644
index 1682eb991..000000000
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/DmaapSimConstants.java
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * ============LICENSE_START=======================================================
- *  Copyright (C) 2019 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.models.sim.dmaap;
-
-/**
- * Names of various items contained in the Registry.
- */
-public class DmaapSimConstants {
-
-    // Registry keys
-    public static final String REG_DMAAP_SIM_ACTIVATOR = "object:activator/dmaap-sim";
-
-    private DmaapSimConstants() {
-        super();
-    }
-}
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterGroup.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterGroup.java
index caae287b8..11da57582 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterGroup.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterGroup.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2019 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.
@@ -21,8 +22,8 @@
 package org.onap.policy.models.sim.dmaap.parameters;
 
 import lombok.Getter;
-
 import org.onap.policy.common.parameters.ParameterGroupImpl;
+import org.onap.policy.common.parameters.annotations.Min;
 import org.onap.policy.common.parameters.annotations.NotBlank;
 import org.onap.policy.common.parameters.annotations.NotNull;
 
@@ -36,6 +37,14 @@ public class DmaapSimParameterGroup extends ParameterGroupImpl {
     private RestServerParameters restServerParameters;
 
     /**
+     * Frequency, in seconds, with which to sweep the topics of idle consumers. On each
+     * sweep cycle, if a consumer group has had no new poll requests since the last sweep
+     * cycle, it is removed.
+     */
+    @Min(1)
+    private long topicSweepSec;
+
+    /**
      * Create the DMaaP simulator parameter group.
      *
      * @param name the parameter group name
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterHandler.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterHandler.java
index 8eb76ec00..252054504 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterHandler.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/DmaapSimParameterHandler.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2019 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.
@@ -38,7 +39,7 @@ public class DmaapSimParameterHandler {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(DmaapSimParameterHandler.class);
 
-    private static final Coder CODER = new StandardCoder();
+    private final Coder coder = new StandardCoder();
 
     /**
      * Read the parameters from the parameter file.
@@ -54,7 +55,7 @@ public class DmaapSimParameterHandler {
         try {
             // Read the parameters from JSON
             File file = new File(arguments.getFullConfigurationFilePath());
-            dmaapSimParameterGroup = CODER.decode(file, DmaapSimParameterGroup.class);
+            dmaapSimParameterGroup = coder.decode(file, DmaapSimParameterGroup.class);
         } catch (final CoderException e) {
             final String errorMessage = "error reading parameters from \"" + arguments.getConfigurationFilePath()
                     + "\"\n" + "(" + e.getClass().getSimpleName() + "):" + e.getMessage();
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/RestServerParameters.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/RestServerParameters.java
index c7269f66d..8fb2cffa3 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/RestServerParameters.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/parameters/RestServerParameters.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2019 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.
@@ -21,13 +22,14 @@
 package org.onap.policy.models.sim.dmaap.parameters;
 
 import lombok.Getter;
+
 import org.onap.policy.common.parameters.ParameterGroupImpl;
 import org.onap.policy.common.parameters.annotations.Min;
 import org.onap.policy.common.parameters.annotations.NotBlank;
 import org.onap.policy.common.parameters.annotations.NotNull;
 
 /**
- * Class to hold all parameters needed for DMaaP simulator rest server.
+ * Class to hold all parameters needed for rest server.
  */
 @NotNull
 @NotBlank
@@ -39,6 +41,6 @@ public class RestServerParameters extends ParameterGroupImpl {
     private int port;
 
     public RestServerParameters() {
-        super("RestServerParameters");
+        super(RestServerParameters.class.getSimpleName());
     }
 }
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/ConsumerGroupData.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/ConsumerGroupData.java
new file mode 100644
index 000000000..737151339
--- /dev/null
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/ConsumerGroupData.java
@@ -0,0 +1,190 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Models
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.models.sim.dmaap.provider;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Data associated with a consumer group. All consumer instances within a group share the
+ * same data object.
+ */
+public class ConsumerGroupData {
+    private static final Logger logger = LoggerFactory.getLogger(ConsumerGroupData.class);
+
+    /**
+     * Returned when messages can no longer be read from this consumer group object,
+     * because it is being removed from the topic. {@link #UNREADABLE_LIST} must not be
+     * the same list as Collections.emptyList(), thus we wrap it.
+     */
+    public static final List<String> UNREADABLE_LIST = Collections.unmodifiableList(Collections.emptyList());
+
+    /**
+     * Returned when there are no messages read. Collections.emptyList() is already
+     * unmodifiable, thus no need to wrap it.
+     */
+    private static final List<String> EMPTY_LIST = Collections.emptyList();
+
+    /**
+     * This is locked while fields other than {@link #messageQueue} are updated.
+     */
+    private final Object lockit = new Object();
+
+    /**
+     * Number of sweep cycles that have occurred since a consumer has attempted to read
+     * from the queue. This consumer group should be removed once this count exceeds
+     * {@code 1}, provided {@link #nreaders} is zero.
+     */
+    private int nsweeps = 0;
+
+    /**
+     * Number of consumers that are currently attempting to read from the queue. This
+     * consumer group should not be removed as long as this is non-zero.
+     */
+    private int nreaders = 0;
+
+    /**
+     * Message queue.
+     */
+    private final BlockingQueue<String> messageQueue = new LinkedBlockingQueue<>();
+
+
+    /**
+     * Constructs the object.
+     *
+     * @param topicName name of the topic with which this object is associated
+     * @param groupName name of the consumer group with which this object is associated
+     */
+    public ConsumerGroupData(String topicName, String groupName) {
+        logger.info("Topic {}: add consumer group: {}", topicName, groupName);
+    }
+
+    /**
+     * Determines if this consumer group should be removed. This should be invoked once
+     * during each sweep cycle. When this returns {@code true}, this consumer group should
+     * be immediately discarded, as any readers will sit in a spin loop waiting for it to
+     * be discarded.
+     *
+     * @return {@code true} if this consumer group should be removed, {@code false}
+     *         otherwise
+     */
+    public boolean shouldRemove() {
+        synchronized (lockit) {
+            return (nreaders == 0 && ++nsweeps > 1);
+        }
+    }
+
+    /**
+     * Reads messages from the queue, blocking if necessary.
+     *
+     * @param maxRead maximum number of messages to read
+     * @param waitMs time to wait, in milliseconds, if the queue is currently empty
+     * @return a list of messages read from the queue, empty if no messages became
+     *         available before the wait time elapsed, or {@link #UNREADABLE_LIST} if this
+     *         consumer group object is no longer active
+     * @throws InterruptedException if this thread was interrupted while waiting for the
+     *         first message
+     */
+    public List<String> read(int maxRead, long waitMs) throws InterruptedException {
+
+        synchronized (lockit) {
+            if (nsweeps > 1 && nreaders == 0) {
+                // cannot use this consumer group object anymore
+                return UNREADABLE_LIST;
+            }
+
+            ++nreaders;
+        }
+
+        /*
+         * Note: do EVERYTHING inside of the "try" block, so that the "finally" block can
+         * update the reader count.
+         *
+         * Do NOT hold the lockit while we're polling, as poll() may block for a while.
+         */
+        try {
+            // always read at least one message
+            int maxRead2 = Math.max(1, maxRead);
+            long waitMs2 = Math.max(0, waitMs);
+
+            // perform a blocking read of the queue
+            String obj = getNextMessage(waitMs2);
+            if (obj == null) {
+                return EMPTY_LIST;
+            }
+
+            /*
+             * List should hold all messages from the queue PLUS the one we already have.
+             * Note: it's possible for additional messages to be added to the queue while
+             * we're reading from it. In that case, the list will grow as needed.
+             */
+            List<String> lst = new ArrayList<>(Math.min(maxRead2, messageQueue.size() + 1));
+            lst.add(obj);
+
+            // perform NON-blocking read of subsequent messages
+            for (int x = 1; x < maxRead2; ++x) {
+                if ((obj = messageQueue.poll()) == null) {
+                    break;
+                }
+
+                lst.add(obj);
+            }
+
+            return lst;
+
+        } finally {
+            synchronized (lockit) {
+                --nreaders;
+                nsweeps = 0;
+            }
+        }
+    }
+
+    /**
+     * Writes messages to the queue.
+     *
+     * @param messages messages to be written to the queue
+     */
+    public void write(List<String> messages) {
+        messageQueue.addAll(messages);
+    }
+
+    // the following methods may be overridden by junit tests
+
+    /**
+     * Gets the next message from the queue.
+     *
+     * @param waitMs time to wait, in milliseconds, if the queue is currently empty
+     * @return the next message, or {@code null} if no messages became available before
+     *         the wait time elapsed
+     * @throws InterruptedException if this thread was interrupted while waiting for the
+     *         message
+     */
+    protected String getNextMessage(long waitMs) throws InterruptedException {
+        return messageQueue.poll(waitMs, TimeUnit.MILLISECONDS);
+    }
+}
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/DmaapSimProvider.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/DmaapSimProvider.java
index 9de29cdac..d11d1b397 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/DmaapSimProvider.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/DmaapSimProvider.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2019 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.
@@ -20,18 +21,20 @@
 
 package org.onap.policy.models.sim.dmaap.provider;
 
+import java.util.Collections;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
-import java.util.SortedMap;
-import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
-
 import javax.ws.rs.core.Response;
-
-import org.apache.commons.lang3.tuple.MutablePair;
-import org.onap.policy.common.utils.coder.CoderException;
-import org.onap.policy.common.utils.coder.StandardCoder;
-import org.onap.policy.models.sim.dmaap.DmaapSimRuntimeException;
+import javax.ws.rs.core.Response.Status;
+import lombok.Getter;
+import lombok.Setter;
+import org.onap.policy.common.utils.services.ServiceManagerContainer;
+import org.onap.policy.models.sim.dmaap.parameters.DmaapSimParameterGroup;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -40,50 +43,70 @@ import org.slf4j.LoggerFactory;
  *
  * @author Liam Fallon (liam.fallon@est.tech)
  */
-public class DmaapSimProvider {
+public class DmaapSimProvider extends ServiceManagerContainer {
     private static final Logger LOGGER = LoggerFactory.getLogger(DmaapSimProvider.class);
 
-    // Recurring string constants
-    private static final String TOPIC_TAG = "Topic:";
+    @Getter
+    @Setter
+    private static DmaapSimProvider instance;
 
-    // Time for a get to wait before checking of a message has come
-    private static final long DMAAP_SIM_WAIT_TIME = 50;
+    /**
+     * Maps a topic name to its data.
+     */
+    private final Map<String, TopicData> topic2data = new ConcurrentHashMap<>();
 
-    // recurring constants
-    private static final String WITH_TIMEOUT = " with timeout ";
+    /**
+     * Thread used to remove idle consumers from the topics.
+     */
+    private ScheduledExecutorService timerPool;
 
-    // The map of topic messages
-    private static final Map<String, SortedMap<Integer, Object>> topicMessageMap = new LinkedHashMap<>();
 
-    // The map of topic messages
-    private static final Map<String, Map<String, MutablePair<Integer, String>>> consumerGroupsMap =
-            new LinkedHashMap<>();
+    /**
+     * Constructs the object.
+     *
+     * @param params parameters
+     */
+    public DmaapSimProvider(DmaapSimParameterGroup params) {
+        addAction("Topic Sweeper", () -> {
+            timerPool = makeTimerPool();
+            timerPool.scheduleWithFixedDelay(new SweeperTask(), params.getTopicSweepSec(), params.getTopicSweepSec(),
+                            TimeUnit.SECONDS);
+        }, () -> timerPool.shutdown());
+    }
 
     /**
      * Process a DMaaP message.
      *
-     * @param topicName The topic name
+     * @param topicName the topic name
      * @param dmaapMessage the message to process
      * @return a response to the message
      */
+    @SuppressWarnings("unchecked")
     public Response processDmaapMessagePut(final String topicName, final Object dmaapMessage) {
-        LOGGER.debug(TOPIC_TAG + topicName + ", Received DMaaP message: " + dmaapMessage);
-
-        synchronized (topicMessageMap) {
-            SortedMap<Integer, Object> messageMap = topicMessageMap.get(topicName);
-            if (messageMap == null) {
-                messageMap = new TreeMap<>();
-                topicMessageMap.put(topicName, messageMap);
-                LOGGER.debug(TOPIC_TAG + topicName + ", created topic message map");
-            }
+        LOGGER.debug("Topic: {}, Received DMaaP message(s): {}", topicName, dmaapMessage);
 
-            int nextKey = (messageMap.isEmpty() ? 0 : messageMap.lastKey() + 1);
+        List<Object> lst;
 
-            messageMap.put(nextKey, dmaapMessage);
-            LOGGER.debug(TOPIC_TAG + topicName + ", cached DMaaP message " + nextKey + ": " + dmaapMessage);
+        if (dmaapMessage instanceof List) {
+            lst = (List<Object>) dmaapMessage;
+        } else {
+            lst = Collections.singletonList(dmaapMessage);
         }
 
-        return Response.status(Response.Status.OK).entity("{\n    \"serverTimeMs\": 0,\n    \"count\": 1\n}").build();
+        TopicData topic = topic2data.get(topicName);
+
+        /*
+         * Write all messages and return the count. If the topic doesn't exist yet, then
+         * there are no subscribers to receive the messages, thus treat it as if all
+         * messages were published.
+         */
+        int nmessages = (topic != null ? topic.write(lst) : lst.size());
+
+        Map<String, Object> map = new LinkedHashMap<>();
+        map.put("serverTimeMs", 0);
+        map.put("count", nmessages);
+
+        return Response.status(Response.Status.OK).entity(map).build();
     }
 
     /**
@@ -92,102 +115,66 @@ public class DmaapSimProvider {
      * @param topicName The topic to wait on
      * @param consumerGroup the consumer group that is waiting
      * @param consumerId the consumer ID that is waiting
-     * @param timeout the length of time to wait for
+     * @param limit the maximum number of messages to get
+     * @param timeoutMs the length of time to wait for
      * @return the DMaaP message or
      */
     public Response processDmaapMessageGet(final String topicName, final String consumerGroup, final String consumerId,
-            final int timeout) {
+                    final int limit, final long timeoutMs) {
 
-        LOGGER.debug(TOPIC_TAG + topicName + ", Request for DMaaP message: " + consumerGroup + ":" + consumerId
-                + WITH_TIMEOUT + timeout);
+        LOGGER.debug("Topic: {}, Request for DMaaP message: {}: {} with limit={} timeout={}", topicName, consumerGroup,
+                        consumerId, limit, timeoutMs);
 
-        MutablePair<Integer, String> consumerGroupPair = null;
-
-        synchronized (consumerGroupsMap) {
-            Map<String, MutablePair<Integer, String>> consumerGroupMap = consumerGroupsMap.get(topicName);
-            if (consumerGroupMap == null) {
-                consumerGroupMap = new LinkedHashMap<>();
-                consumerGroupsMap.put(topicName, consumerGroupMap);
-                LOGGER.trace(
-                        TOPIC_TAG + topicName + ", Created consumer map entry for consumer group " + consumerGroup);
-            }
-
-            consumerGroupPair = consumerGroupMap.get(consumerGroup);
-            if (consumerGroupPair == null) {
-                consumerGroupPair = new MutablePair<>(-1, consumerId);
-                consumerGroupMap.put(consumerGroup, consumerGroupPair);
-                LOGGER.trace(TOPIC_TAG + topicName + ", Created consumer group entry for consumer group "
-                        + consumerGroup + ":" + consumerId);
-            }
-        }
+        try {
+            List<String> lst = topic2data.computeIfAbsent(topicName, this::makeTopicData).read(consumerGroup, limit,
+                            timeoutMs);
 
-        long timeOfTimeout = System.currentTimeMillis() + timeout;
+            if (lst.isEmpty() && timeoutMs > 0) {
+                LOGGER.debug("Topic: {}, Timed out waiting for messages: {}: {}", topicName, consumerGroup, consumerId);
+                return Response.status(Status.REQUEST_TIMEOUT).entity(lst).build();
 
-        do {
-            Object waitingMessages = getWaitingMessages(topicName, consumerGroupPair);
-            if (waitingMessages != null) {
-                LOGGER.debug(TOPIC_TAG + topicName + ", Request for DMaaP message: " + consumerGroup + ":" + consumerId
-                        + WITH_TIMEOUT + timeout + ", returning messages " + waitingMessages);
-                return Response.status(Response.Status.OK).entity(waitingMessages).build();
+            } else {
+                LOGGER.debug("Topic: {}, Retrieved {} messages for: {}: {}", topicName, consumerGroup, lst.size(),
+                                consumerId);
+                return Response.status(Status.OK).entity(lst).build();
             }
 
-            try {
-                TimeUnit.MILLISECONDS.sleep(DMAAP_SIM_WAIT_TIME);
-            } catch (InterruptedException ie) {
-                String errorMessage = "Interrupt on wait on simulation of DMaaP topic " + topicName + " for request ID "
-                        + consumerGroup + ":" + consumerId + WITH_TIMEOUT + timeout;
-                LOGGER.warn(errorMessage, ie);
-                Thread.currentThread().interrupt();
-                throw new DmaapSimRuntimeException(errorMessage, ie);
-            }
+        } catch (InterruptedException e) {
+            LOGGER.warn("Topic: {}, Request for DMaaP message interrupted: {}: {}", topicName, consumerGroup,
+                            consumerId, e);
+            Thread.currentThread().interrupt();
+            return Response.status(Status.GONE).entity(Collections.emptyList()).build();
         }
-        while (timeOfTimeout > System.currentTimeMillis());
-
-        LOGGER.trace(TOPIC_TAG + topicName + ", timed out waiting for messages : " + consumerGroup + ":" + consumerId
-                + WITH_TIMEOUT + timeout);
-        return Response.status(Response.Status.REQUEST_TIMEOUT).build();
     }
 
     /**
-     * Return any messages on this topic with a message number greater than the supplied message number.
-     *
-     * @param topicName the topic name to check
-     * @param consumerGroupPair the pair with the information on the last message retrieved
-     * @return the messages or null if there are none
+     * Task to remove idle consumers from each topic.
      */
-    private Object getWaitingMessages(final String topicName, final MutablePair<Integer, String> consumerGroupPair) {
-        String foundMessageList = "[";
-
-        synchronized (topicMessageMap) {
-            SortedMap<Integer, Object> messageMap = topicMessageMap.get(topicName);
-            if (messageMap == null || messageMap.lastKey() <= consumerGroupPair.getLeft()) {
-                return null;
-            }
+    private class SweeperTask implements Runnable {
+        @Override
+        public void run() {
+            topic2data.values().forEach(TopicData::removeIdleConsumers);
+        }
+    }
 
-            boolean first = true;
-            for (Object dmaapMessage : messageMap.tailMap(consumerGroupPair.getLeft() + 1).values()) {
-                if (first) {
-                    first = false;
-                } else {
-                    foundMessageList += ",";
-                }
-                try {
-                    foundMessageList += new StandardCoder().encode(dmaapMessage);
-                } catch (CoderException ce) {
-                    String errorMessage = "Encoding error on message on DMaaP topic " + topicName;
-                    LOGGER.warn(errorMessage, ce);
-                    return null;
-                }
-            }
-            foundMessageList += ']';
+    // the following methods may be overridden by junit tests
 
-            LOGGER.debug(TOPIC_TAG + topicName + ", returning DMaaP messages from  " + consumerGroupPair.getLeft()
-                    + " to " + messageMap.lastKey());
-            synchronized (consumerGroupsMap) {
-                consumerGroupPair.setLeft(messageMap.lastKey());
-            }
-        }
+    /**
+     * Makes a new timer pool.
+     *
+     * @return a new timer pool
+     */
+    protected ScheduledExecutorService makeTimerPool() {
+        return Executors.newScheduledThreadPool(1);
+    }
 
-        return (foundMessageList.length() < 3 ? null : foundMessageList);
+    /**
+     * Makes a new topic.
+     *
+     * @param topicName topic name
+     * @return a new topic
+     */
+    protected TopicData makeTopicData(String topicName) {
+        return new TopicData(topicName);
     }
 }
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/TopicData.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/TopicData.java
new file mode 100644
index 000000000..2737f455b
--- /dev/null
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/provider/TopicData.java
@@ -0,0 +1,201 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Models
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.models.sim.dmaap.provider;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+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;
+
+/**
+ * Data associated with a topic.
+ *
+ * <p/>
+ * Note: for ease of implementation, this adds a topic when a consumer polls it rather
+ * than when a publisher writes to it. This is the opposite of how the real DMaaP works.
+ * As a result, this will never return a topic-not-found message to the consumer.
+ */
+public class TopicData {
+    private static final Logger logger = LoggerFactory.getLogger(TopicData.class);
+
+    /**
+     * Name of the topic with which this data is associated.
+     */
+    private final String topicName;
+
+    /**
+     * Maps a consumer group name to its associated data.
+     */
+    private final Map<String, ConsumerGroupData> group2data = new ConcurrentHashMap<>();
+
+
+    /**
+     * Constructs the object.
+     *
+     * @param topicName name of the topic with which this object is associated
+     */
+    public TopicData(String topicName) {
+        logger.info("Topic {}: added", topicName);
+        this.topicName = topicName;
+    }
+
+    /**
+     * Removes idle consumers from the topic. This is typically called once during each
+     * sweep cycle.
+     */
+    public void removeIdleConsumers() {
+        Iterator<Entry<String, ConsumerGroupData>> iter = group2data.entrySet().iterator();
+        while (iter.hasNext()) {
+            Entry<String, ConsumerGroupData> ent = iter.next();
+            if (ent.getValue().shouldRemove()) {
+                /*
+                 * We want the minimum amount of time to elapse between invoking
+                 * shouldRemove() and iter.remove(), thus all other statements (e.g.,
+                 * logging) should be done AFTER iter.remove().
+                 */
+                iter.remove();
+
+                logger.info("Topic {}: removed consumer group: {}", topicName, ent.getKey());
+            }
+        }
+    }
+
+    /**
+     * Reads from a particular consumer group's queue.
+     *
+     * @param consumerGroup name of the consumer group from which to read
+     * @param maxRead maximum number of messages to read
+     * @param waitMs time to wait, in milliseconds, if the queue is currently empty
+     * @return a list of messages read from the queue, empty if no messages became
+     *         available before the wait time elapsed
+     * @throws InterruptedException if this thread was interrupted while waiting for the
+     *         first message
+     */
+    public List<String> read(String consumerGroup, int maxRead, long waitMs) throws InterruptedException {
+        /*
+         * It's possible that this thread may spin several times while waiting for
+         * removeIdleConsumers() to complete its call to iter.remove(), thus we create
+         * this closure once, rather than each time through the loop.
+         */
+        Function<String, ConsumerGroupData> maker = this::makeData;
+
+        // loop until we get a readable list
+        List<String> result;
+
+        // @formatter:off
+
+        do {
+            result = group2data.computeIfAbsent(consumerGroup, maker).read(maxRead, waitMs);
+        }
+        while (result == ConsumerGroupData.UNREADABLE_LIST);
+
+        // @formatter:on
+
+        return result;
+    }
+
+    /**
+     * Writes messages to the queues of every consumer group.
+     *
+     * @param messages messages to be written to the queues
+     * @return the number of messages enqueued
+     */
+    public int write(List<Object> messages) {
+        List<String> list = convertMessagesToStrings(messages);
+
+        /*
+         * We don't care if a consumer group is deleted from the map while we're adding
+         * messages to it, as those messages will simply be ignored (and discarded by the
+         * garbage collector).
+         */
+        for (ConsumerGroupData data : group2data.values()) {
+            data.write(list);
+        }
+
+        return list.size();
+    }
+
+    /**
+     * Converts a list of message objects to a list of message strings. If a message
+     * cannot be converted for some reason, then it is not added to the result list, thus
+     * the result list may be shorted than the original input list.
+     *
+     * @param messages objects to be converted
+     * @return a list of message strings
+     */
+    protected List<String> convertMessagesToStrings(List<Object> messages) {
+        Coder coder = new StandardCoder();
+        List<String> list = new ArrayList<>(messages.size());
+
+        for (Object msg : messages) {
+            String str = convertMessageToString(msg, coder);
+            if (str != null) {
+                list.add(str);
+            }
+        }
+
+        return list;
+    }
+
+    /**
+     * Converts a message object to a message string.
+     *
+     * @param message message to be converted
+     * @param coder used to encode the message as a string
+     * @return the message string, or {@code null} if it cannot be converted
+     */
+    protected String convertMessageToString(Object message, Coder coder) {
+        if (message == null) {
+            return null;
+        }
+
+        if (message instanceof String) {
+            return message.toString();
+        }
+
+        try {
+            return coder.encode(message);
+        } catch (CoderException e) {
+            logger.warn("cannot encode {}", message, e);
+            return null;
+        }
+    }
+
+    // this may be overridden by junit tests
+
+    /**
+     * Makes data for a consumer group.
+     *
+     * @param consumerGroup name of the consumer group to make
+     * @return new consumer group data
+     */
+    protected ConsumerGroupData makeData(String consumerGroup) {
+        return new ConsumerGroupData(topicName, consumerGroup);
+    }
+}
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/CambriaMessageBodyHandler.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/CambriaMessageBodyHandler.java
index e269ac00b..dbd9422ef 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/CambriaMessageBodyHandler.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/CambriaMessageBodyHandler.java
@@ -1,66 +1,178 @@
-/*
- * ============LICENSE_START======================================================= ONAP
- * ================================================================================ 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
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Models
+ * ================================================================================
+ * 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
+ *      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.
+ * 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.models.sim.dmaap.rest;
 
 import java.io.BufferedReader;
+import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.io.Reader;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Type;
+import java.nio.charset.StandardCharsets;
+import java.util.LinkedList;
+import java.util.List;
 import javax.ws.rs.Consumes;
-import javax.ws.rs.Produces;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.MultivaluedMap;
 import javax.ws.rs.ext.MessageBodyReader;
 import javax.ws.rs.ext.Provider;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.apache.commons.io.IOUtils;
 
 /**
- * Provider that serializes and de-serializes JSON via gson.
+ * Provider that decodes "application/cambria" messages.
  */
 @Provider
 @Consumes(CambriaMessageBodyHandler.MEDIA_TYPE_APPLICATION_CAMBRIA)
-@Produces(CambriaMessageBodyHandler.MEDIA_TYPE_APPLICATION_CAMBRIA)
 public class CambriaMessageBodyHandler implements MessageBodyReader<Object> {
-    // Media type for Cambria
     public static final String MEDIA_TYPE_APPLICATION_CAMBRIA = "application/cambria";
 
-    public static final Logger logger = LoggerFactory.getLogger(CambriaMessageBodyHandler.class);
+    /**
+     * Maximum length of a message or partition.
+     */
+    private static final int MAX_LEN = 10000000;
+
+    /**
+     * Maximum digits in a length field.
+     */
+    private static final int MAX_DIGITS = 10;
 
     @Override
     public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
-        return MEDIA_TYPE_APPLICATION_CAMBRIA.equals(mediaType.toString());
+        return (mediaType != null && MEDIA_TYPE_APPLICATION_CAMBRIA.equals(mediaType.toString()));
     }
 
     @Override
-    public String readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType,
-            MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
-            throws IOException {
-
-        String cambriaString = "";
-        try (BufferedReader bufferedReader = new BufferedReader(
-                new InputStreamReader(entityStream))) {
-            String line;
-            while ((line = bufferedReader.readLine()) != null) {
-                cambriaString += line;
+    public List<Object> readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType,
+                    MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException {
+
+        try (BufferedReader bufferedReader =
+                        new BufferedReader(new InputStreamReader(entityStream, StandardCharsets.UTF_8))) {
+            List<Object> messages = new LinkedList<>();
+            String msg;
+            while ((msg = readMessage(bufferedReader)) != null) {
+                messages.add(msg);
+            }
+
+            return messages;
+        }
+    }
+
+    /**
+     * Reads a message.
+     *
+     * @param reader source from which to read
+     * @return the message that was read, or {@code null} if there are no more messages
+     * @throws IOException if an error occurs
+     */
+    private String readMessage(Reader reader) throws IOException {
+        if (!skipWhitespace(reader)) {
+            return null;
+        }
+
+        int partlen = readLength(reader);
+        if (partlen > MAX_LEN) {
+            throw new IOException("invalid partition length");
+        }
+
+        int msglen = readLength(reader);
+        if (msglen > MAX_LEN) {
+            throw new IOException("invalid message length");
+        }
+
+        // skip over the partition
+        reader.skip(partlen);
+
+        return readString(reader, msglen);
+    }
+
+    /**
+     * Skips whitespace.
+     *
+     * @param reader source from which to read
+     * @return {@code true} if there is another character after the whitespace,
+     *         {@code false} if the end of the stream has been reached
+     * @throws IOException if an error occurs
+     */
+    private boolean skipWhitespace(Reader reader) throws IOException {
+        int chr;
+
+        do {
+            reader.mark(1);
+            if ((chr = reader.read()) < 0) {
+                return false;
+            }
+        }
+        while (Character.isWhitespace(chr));
+
+        // push the last character back onto the reader
+        reader.reset();
+
+        return true;
+    }
+
+    /**
+     * Reads a length field, which is a number followed by ".".
+     *
+     * @param reader source from which to read
+     * @return the length, or -1 if EOF has been reached
+     * @throws IOException if an error occurs
+     */
+    private int readLength(Reader reader) throws IOException {
+        StringBuilder bldr = new StringBuilder(MAX_DIGITS);
+
+        int chr;
+        for (int x = 0; x < MAX_DIGITS; ++x) {
+            if ((chr = reader.read()) < 0) {
+                throw new EOFException("missing '.' in 'length' field");
             }
 
-            return cambriaString.substring(cambriaString.indexOf('{'), cambriaString.length());
+            if (chr == '.') {
+                String text = bldr.toString().trim();
+                return (text.isEmpty() ? 0 : Integer.valueOf(text));
+            }
+
+            if (!Character.isDigit(chr)) {
+                throw new IOException("invalid character in 'length' field");
+            }
+
+            bldr.append((char) chr);
         }
+
+        throw new IOException("too many digits in 'length' field");
+    }
+
+    /**
+     * Reads a string.
+     *
+     * @param reader source from which to read
+     * @param len length of the string (i.e., number of characters to read)
+     * @return the string that was read
+     * @throws IOException if an error occurs
+     */
+    private String readString(Reader reader, int len) throws IOException {
+        char[] buf = new char[len];
+        IOUtils.readFully(reader, buf);
+
+        return new String(buf);
     }
 }
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestControllerV1.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestControllerV1.java
index e3fdd4884..8339d0e64 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestControllerV1.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestControllerV1.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2019 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.
@@ -20,24 +21,24 @@
 
 package org.onap.policy.models.sim.dmaap.rest;
 
-import io.swagger.annotations.ApiOperation;
-import io.swagger.annotations.ApiResponse;
-import io.swagger.annotations.ApiResponses;
-import io.swagger.annotations.Authorization;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.DefaultValue;
 import javax.ws.rs.GET;
 import javax.ws.rs.POST;
 import javax.ws.rs.Path;
 import javax.ws.rs.PathParam;
+import javax.ws.rs.Produces;
 import javax.ws.rs.QueryParam;
 import javax.ws.rs.core.Response;
-
 import org.onap.policy.models.sim.dmaap.provider.DmaapSimProvider;
 
 /**
  * Class to provide REST endpoints for DMaaP simulator component statistics.
  */
 @Path("/events")
+@Produces(DmaapSimRestControllerV1.MEDIA_TYPE_APPLICATION_JSON)
 public class DmaapSimRestControllerV1 extends BaseRestControllerV1 {
+    public static final String MEDIA_TYPE_APPLICATION_JSON = "application/json";
 
     /**
      * Get a DMaaP message.
@@ -45,72 +46,33 @@ public class DmaapSimRestControllerV1 extends BaseRestControllerV1 {
      * @param topicName topic to get message from
      * @param consumerGroup consumer group that is getting the message
      * @param consumerId consumer ID that is getting the message
-     * @param timeout timeout for the message
+     * @param timeoutMs timeout for the message
      * @return the message
      */
     @GET
     @Path("{topicName}/{consumerGroup}/{consumerId}")
-    // @formatter:off
-    @ApiOperation(
-            value = "Get a DMaaP event on a topic",
-            notes = "Returns an event on a DMaaP topic",
-            response = Object.class,
-            authorizations =
-                @Authorization(value = AUTHORIZATION_TYPE)
-        )
-    @ApiResponses(
-            value = {
-                @ApiResponse(
-                        code = AUTHENTICATION_ERROR_CODE,
-                        message = AUTHENTICATION_ERROR_MESSAGE),
-                @ApiResponse(
-                        code = AUTHORIZATION_ERROR_CODE,
-                        message = AUTHORIZATION_ERROR_MESSAGE),
-                @ApiResponse(
-                        code = SERVER_ERROR_CODE,
-                        message = SERVER_ERROR_MESSAGE)
-            }
-        )
-    // @formatter:on
-    public Response getDmaaapMessage(@PathParam("topicName") final String topicName,
-            @PathParam("consumerGroup") final String consumerGroup, @PathParam("consumerId") final String consumerId,
-            @QueryParam("timeout") final int timeout) {
+    public Response getDmaapMessage(@PathParam("topicName") final String topicName,
+                    @PathParam("consumerGroup") final String consumerGroup,
+                    @PathParam("consumerId") final String consumerId,
+                    @QueryParam("limit") @DefaultValue("1") final int limit,
+                    @QueryParam("timeout") @DefaultValue("15000") final long timeoutMs) {
 
-        return new DmaapSimProvider().processDmaapMessageGet(topicName, consumerGroup, consumerId, timeout);
+        return DmaapSimProvider.getInstance().processDmaapMessageGet(topicName, consumerGroup, consumerId, limit,
+                        timeoutMs);
     }
 
     /**
      * Post a DMaaP message.
      *
-     * @param topicName topic to get message from415
+     * @param topicName topic to get message from
      * @return the response to the post
      */
     @POST
     @Path("{topicName}")
-    // @formatter:off
-    @ApiOperation(
-            value = "Post a DMaaP event on a topic",
-            notes = "Returns an event on a DMaaP topic",
-            response = Response.class,
-            authorizations =
-                @Authorization(value = AUTHORIZATION_TYPE)
-        )
-    @ApiResponses(
-            value = {
-                @ApiResponse(
-                        code = AUTHENTICATION_ERROR_CODE,
-                        message = AUTHENTICATION_ERROR_MESSAGE),
-                @ApiResponse(
-                        code = AUTHORIZATION_ERROR_CODE,
-                        message = AUTHORIZATION_ERROR_MESSAGE),
-                @ApiResponse(
-                        code = SERVER_ERROR_CODE,
-                        message = SERVER_ERROR_MESSAGE)
-            }
-        )
-    // @formatter:on
-    public Response postDmaaapMessage(@PathParam("topicName") final String topicName, final Object dmaapMessage) {
+    @Consumes(value = {CambriaMessageBodyHandler.MEDIA_TYPE_APPLICATION_CAMBRIA,
+                    TextMessageBodyHandler.MEDIA_TYPE_TEXT_PLAIN, MEDIA_TYPE_APPLICATION_JSON})
+    public Response postDmaapMessage(@PathParam("topicName") final String topicName, final Object dmaapMessage) {
 
-        return new DmaapSimProvider().processDmaapMessagePut(topicName, dmaapMessage);
+        return DmaapSimProvider.getInstance().processDmaapMessagePut(topicName, dmaapMessage);
     }
 }
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestServer.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestServer.java
index 28de42c21..b05a0fe1a 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestServer.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/DmaapSimRestServer.java
@@ -21,28 +21,21 @@
 
 package org.onap.policy.models.sim.dmaap.rest;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Properties;
-
-import org.onap.policy.common.capabilities.Startable;
 import org.onap.policy.common.endpoints.http.server.HttpServletServer;
 import org.onap.policy.common.endpoints.http.server.HttpServletServerFactoryInstance;
 import org.onap.policy.common.endpoints.properties.PolicyEndPointProperties;
+import org.onap.policy.common.gson.GsonMessageBodyHandler;
+import org.onap.policy.common.utils.services.ServiceManagerContainer;
 import org.onap.policy.models.sim.dmaap.parameters.RestServerParameters;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * Class to manage life cycle of DMaaP Simulator rest server.
  */
-public class DmaapSimRestServer implements Startable {
-
-    private static final Logger LOGGER = LoggerFactory.getLogger(DmaapSimRestServer.class);
+public class DmaapSimRestServer extends ServiceManagerContainer {
 
-    private List<HttpServletServer> servers = new ArrayList<>();
-
-    private RestServerParameters restServerParameters;
+    private final List<HttpServletServer> servers;
 
     /**
      * Constructor for instantiating DmaapSimRestServer.
@@ -50,91 +43,40 @@ public class DmaapSimRestServer implements Startable {
      * @param restServerParameters the rest server parameters
      */
     public DmaapSimRestServer(final RestServerParameters restServerParameters) {
-        this.restServerParameters = restServerParameters;
-    }
+        this.servers = HttpServletServerFactoryInstance.getServerFactory()
+                        .build(getServerProperties(restServerParameters));
 
-    /**
-     * {@inheritDoc}.
-     */
-    @Override
-    public boolean start() {
-        try {
-            servers = HttpServletServerFactoryInstance.getServerFactory().build(getServerProperties());
-            for (final HttpServletServer server : servers) {
-                server.start();
-            }
-        } catch (final Exception exp) {
-            LOGGER.error("Failed to start DMaaP simulator http server", exp);
-            return false;
+        for (HttpServletServer server : this.servers) {
+            addAction("REST " + server.getName(), server::start, server::stop);
         }
-        return true;
     }
 
     /**
-     * Creates the server properties object using restServerParameters.
+     * Creates a set of properties, suitable for building a REST server, from the
+     * parameters.
      *
-     * @return the properties object
+     * @param restServerParameters parameters from which to build the properties
+     * @return a set of properties representing the given parameters
      */
-    private Properties getServerProperties() {
+    public static Properties getServerProperties(RestServerParameters restServerParameters) {
         final Properties props = new Properties();
         props.setProperty(PolicyEndPointProperties.PROPERTY_HTTP_SERVER_SERVICES, restServerParameters.getName());
 
         final String svcpfx =
-                PolicyEndPointProperties.PROPERTY_HTTP_SERVER_SERVICES + "." + restServerParameters.getName();
+                        PolicyEndPointProperties.PROPERTY_HTTP_SERVER_SERVICES + "." + restServerParameters.getName();
 
         props.setProperty(svcpfx + PolicyEndPointProperties.PROPERTY_HTTP_HOST_SUFFIX, restServerParameters.getHost());
         props.setProperty(svcpfx + PolicyEndPointProperties.PROPERTY_HTTP_PORT_SUFFIX,
-                Integer.toString(restServerParameters.getPort()));
+                        Integer.toString(restServerParameters.getPort()));
         props.setProperty(svcpfx + PolicyEndPointProperties.PROPERTY_HTTP_REST_CLASSES_SUFFIX,
-                String.join(",", DmaapSimRestControllerV1.class.getName()));
+                        DmaapSimRestControllerV1.class.getName());
         props.setProperty(svcpfx + PolicyEndPointProperties.PROPERTY_MANAGED_SUFFIX, "false");
-        props.setProperty(svcpfx + PolicyEndPointProperties.PROPERTY_HTTP_SWAGGER_SUFFIX, "true");
+        props.setProperty(svcpfx + PolicyEndPointProperties.PROPERTY_HTTP_SWAGGER_SUFFIX, "false");
+
         props.setProperty(svcpfx + PolicyEndPointProperties.PROPERTY_HTTP_SERIALIZATION_PROVIDER,
-                CambriaMessageBodyHandler.class.getName() + "," + JsonMessageBodyHandler.class.getName());
+                        String.join(",", CambriaMessageBodyHandler.class.getName(),
+                                        GsonMessageBodyHandler.class.getName(),
+                                        TextMessageBodyHandler.class.getName()));
         return props;
     }
-
-    /**
-     * {@inheritDoc}.
-     */
-    @Override
-    public boolean stop() {
-        for (final HttpServletServer server : servers) {
-            try {
-                server.stop();
-            } catch (final Exception exp) {
-                LOGGER.error("Failed to stop DMaaP simulator http server", exp);
-            }
-        }
-        return true;
-    }
-
-    /**
-     * {@inheritDoc}.
-     */
-    @Override
-    public void shutdown() {
-        stop();
-    }
-
-    /**
-     * {@inheritDoc}.
-     */
-    @Override
-    public boolean isAlive() {
-        return !servers.isEmpty();
-    }
-
-    /**
-     * {@inheritDoc}.
-     */
-    @Override
-    public String toString() {
-        final StringBuilder builder = new StringBuilder();
-        builder.append("DmaapSimRestServer [servers=");
-        builder.append(servers);
-        builder.append("]");
-        return builder.toString();
-    }
-
 }
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/JsonMessageBodyHandler.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/JsonMessageBodyHandler.java
deleted file mode 100644
index a3eebda00..000000000
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/JsonMessageBodyHandler.java
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * ============LICENSE_START======================================================= ONAP
- * ================================================================================ 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.
- * ============LICENSE_END=========================================================
- */
-
-package org.onap.policy.models.sim.dmaap.rest;
-
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.lang.annotation.Annotation;
-import java.lang.reflect.Type;
-import javax.ws.rs.Consumes;
-import javax.ws.rs.Produces;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.MultivaluedMap;
-import javax.ws.rs.ext.MessageBodyReader;
-import javax.ws.rs.ext.Provider;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Provider that serializes and de-serializes JSON via gson.
- */
-@Provider
-@Consumes(MediaType.APPLICATION_JSON)
-@Produces(MediaType.APPLICATION_JSON)
-public class JsonMessageBodyHandler implements MessageBodyReader<Object> {
-    public static final Logger logger = LoggerFactory.getLogger(JsonMessageBodyHandler.class);
-
-    @Override
-    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
-        return MediaType.APPLICATION_JSON.equals(mediaType.toString());
-    }
-
-    @Override
-    public String readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType,
-            MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
-            throws IOException {
-
-        String jsonString = "";
-        try (BufferedReader bufferedReader = new BufferedReader(
-                new InputStreamReader(entityStream))) {
-            String line;
-            while ((line = bufferedReader.readLine()) != null) {
-                jsonString += line;
-            }
-
-            return jsonString;
-        }
-    }
-}
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/TextMessageBodyHandler.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/TextMessageBodyHandler.java
new file mode 100644
index 000000000..3c903c82b
--- /dev/null
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/rest/TextMessageBodyHandler.java
@@ -0,0 +1,66 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Models
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.models.sim.dmaap.rest;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Type;
+import java.nio.charset.StandardCharsets;
+import java.util.LinkedList;
+import java.util.List;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.MultivaluedMap;
+import javax.ws.rs.ext.MessageBodyReader;
+import javax.ws.rs.ext.Provider;
+
+/**
+ * Provider that decodes "text/plain" messages.
+ */
+@Provider
+@Consumes(TextMessageBodyHandler.MEDIA_TYPE_TEXT_PLAIN)
+public class TextMessageBodyHandler implements MessageBodyReader<Object> {
+    public static final String MEDIA_TYPE_TEXT_PLAIN = "text/plain";
+
+    @Override
+    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
+        return (mediaType != null && MEDIA_TYPE_TEXT_PLAIN.equals(mediaType.toString()));
+    }
+
+    @Override
+    public List<Object> readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType,
+                    MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException {
+
+        try (BufferedReader bufferedReader =
+                        new BufferedReader(new InputStreamReader(entityStream, StandardCharsets.UTF_8))) {
+            List<Object> messages = new LinkedList<>();
+            String msg;
+            while ((msg = bufferedReader.readLine()) != null) {
+                messages.add(msg);
+            }
+
+            return messages;
+        }
+    }
+}
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimActivator.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimActivator.java
index 899c0e081..b9e0efaaf 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimActivator.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimActivator.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2019 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.
@@ -20,19 +21,15 @@
 
 package org.onap.policy.models.sim.dmaap.startstop;
 
-import org.onap.policy.common.parameters.ParameterService;
 import org.onap.policy.common.utils.services.ServiceManagerContainer;
 import org.onap.policy.models.sim.dmaap.parameters.DmaapSimParameterGroup;
+import org.onap.policy.models.sim.dmaap.provider.DmaapSimProvider;
 import org.onap.policy.models.sim.dmaap.rest.DmaapSimRestServer;
 
 /**
  * This class activates the DMaaP simulator as a complete service.
  */
 public class DmaapSimActivator extends ServiceManagerContainer {
-    /**
-     * The DMaaP simulator REST API server.
-     */
-    private DmaapSimRestServer restServer;
 
     /**
      * Instantiate the activator for the DMaaP simulator as a complete service.
@@ -42,19 +39,11 @@ public class DmaapSimActivator extends ServiceManagerContainer {
     public DmaapSimActivator(final DmaapSimParameterGroup dmaapSimParameterGroup) {
         super("DMaaP Simulator");
 
-        // @formatter:off
-        addAction("DMaaP Simulator parameters",
-            () -> ParameterService.register(dmaapSimParameterGroup),
-            () -> ParameterService.deregister(dmaapSimParameterGroup.getName()));
-
-        addAction("Create REST server",
-            () -> restServer = new DmaapSimRestServer(dmaapSimParameterGroup.getRestServerParameters()),
-            () -> restServer = null
-        );
+        DmaapSimProvider provider = new DmaapSimProvider(dmaapSimParameterGroup);
+        DmaapSimProvider.setInstance(provider);
+        addAction("Sim Provider", provider::start, provider::stop);
 
-        addAction("REST server",
-            () -> restServer.start(),
-            () -> restServer.stop());
-        // @formatter:on
+        DmaapSimRestServer restServer = new DmaapSimRestServer(dmaapSimParameterGroup.getRestServerParameters());
+        addAction("REST server", restServer::start, restServer::stop);
     }
 }
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimCommandLineArguments.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimCommandLineArguments.java
index cf559f712..724c3dc35 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimCommandLineArguments.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/DmaapSimCommandLineArguments.java
@@ -26,13 +26,15 @@ import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.net.URL;
 import java.util.Arrays;
-
+import lombok.Getter;
+import lombok.Setter;
 import org.apache.commons.cli.CommandLine;
 import org.apache.commons.cli.DefaultParser;
 import org.apache.commons.cli.HelpFormatter;
 import org.apache.commons.cli.Option;
 import org.apache.commons.cli.Options;
 import org.apache.commons.cli.ParseException;
+import org.apache.commons.lang3.StringUtils;
 import org.onap.policy.common.utils.resources.ResourceUtils;
 import org.onap.policy.models.sim.dmaap.DmaapSimException;
 import org.onap.policy.models.sim.dmaap.DmaapSimRuntimeException;
@@ -46,6 +48,9 @@ public class DmaapSimCommandLineArguments {
     private static final int HELP_LINE_LENGTH = 120;
 
     private final Options options;
+
+    @Getter
+    @Setter
     private String configurationFilePath = null;
 
     /**
@@ -145,7 +150,7 @@ public class DmaapSimCommandLineArguments {
      * @throws DmaapSimException on command argument validation errors
      */
     public void validate() throws DmaapSimException {
-        validateReadableFile("DMaaP simulator configuration", configurationFilePath);
+        validateFileExists("DMaaP simulator configuration", configurationFilePath);
     }
 
     /**
@@ -175,15 +180,6 @@ public class DmaapSimCommandLineArguments {
     }
 
     /**
-     * Gets the configuration file path.
-     *
-     * @return the configuration file path
-     */
-    public String getConfigurationFilePath() {
-        return configurationFilePath;
-    }
-
-    /**
      * Gets the full expanded configuration file path.
      *
      * @return the configuration file path
@@ -193,16 +189,6 @@ public class DmaapSimCommandLineArguments {
     }
 
     /**
-     * Sets the configuration file path.
-     *
-     * @param configurationFilePath the configuration file path
-     */
-    public void setConfigurationFilePath(final String configurationFilePath) {
-        this.configurationFilePath = configurationFilePath;
-
-    }
-
-    /**
      * Check set configuration file path.
      *
      * @return true, if check set configuration file path
@@ -212,14 +198,14 @@ public class DmaapSimCommandLineArguments {
     }
 
     /**
-     * Validate readable file.
+     * Validate file exists.
      *
      * @param fileTag the file tag
      * @param fileName the file name
      * @throws DmaapSimException on the file name passed as a parameter
      */
-    private void validateReadableFile(final String fileTag, final String fileName) throws DmaapSimException {
-        if (fileName == null || fileName.length() == 0) {
+    private void validateFileExists(final String fileTag, final String fileName) throws DmaapSimException {
+        if (StringUtils.isBlank(fileName)) {
             throw new DmaapSimException(fileTag + " file was not specified as an argument");
         }
 
@@ -233,11 +219,5 @@ public class DmaapSimCommandLineArguments {
         if (!theFile.exists()) {
             throw new DmaapSimException(fileTag + FILE_MESSAGE_PREAMBLE + fileName + "\" does not exist");
         }
-        if (!theFile.isFile()) {
-            throw new DmaapSimException(fileTag + FILE_MESSAGE_PREAMBLE + fileName + "\" is not a normal file");
-        }
-        if (!theFile.canRead()) {
-            throw new DmaapSimException(fileTag + FILE_MESSAGE_PREAMBLE + fileName + "\" is ureadable");
-        }
     }
 }
diff --git a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/Main.java b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/Main.java
index 878d008a8..7b4f41b07 100644
--- a/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/Main.java
+++ b/models-sim/models-sim-dmaap/src/main/java/org/onap/policy/models/sim/dmaap/startstop/Main.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2019 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.
@@ -21,9 +22,6 @@
 package org.onap.policy.models.sim.dmaap.startstop;
 
 import java.util.Arrays;
-
-import org.onap.policy.common.utils.services.Registry;
-import org.onap.policy.models.sim.dmaap.DmaapSimConstants;
 import org.onap.policy.models.sim.dmaap.DmaapSimException;
 import org.onap.policy.models.sim.dmaap.parameters.DmaapSimParameterGroup;
 import org.onap.policy.models.sim.dmaap.parameters.DmaapSimParameterHandler;
@@ -75,14 +73,12 @@ public class Main {
 
         // Now, create the activator for the DMaaP Simulator service
         activator = new DmaapSimActivator(parameterGroup);
-        Registry.register(DmaapSimConstants.REG_DMAAP_SIM_ACTIVATOR, activator);
 
         // Start the activator
         try {
             activator.start();
         } catch (final RuntimeException e) {
             LOGGER.error("start of DMaaP simulator service failed, used parameters are {}", Arrays.toString(args), e);
-            Registry.unregister(DmaapSimConstants.REG_DMAAP_SIM_ACTIVATOR);
             return;
         }
 
@@ -110,7 +106,7 @@ public class Main {
         parameterGroup = null;
 
         // clear the DMaaP simulator activator
-        if (activator != null) {
+        if (activator != null && activator.isAlive()) {
             activator.stop();
         }
     }
@@ -128,8 +124,9 @@ public class Main {
         public void run() {
             try {
                 // Shutdown the DMaaP simulator service and wait for everything to stop
-                activator.stop();
-            } catch (final RuntimeException e) {
+                shutdown();
+
+            } catch (final RuntimeException | DmaapSimException e) {
                 LOGGER.warn("error occured during shut down of the DMaaP simulator service", e);
             }
         }