Merge "Add Network Logging Feature"

16 files changed, 876 insertions, 99 deletions

diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicEndpoint.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicEndpoint.java
index a2ad4d3d..ef002f52 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicEndpoint.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicEndpoint.java
@@ -23,7 +23,8 @@ package org.onap.policy.common.endpoints.event.comm.bus;
 
 import java.util.List;
 import org.onap.policy.common.endpoints.event.comm.bus.internal.TopicBase;
-import org.onap.policy.common.utils.slf4j.LoggerFactoryWrapper;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -38,11 +39,6 @@ public abstract class NoopTopicEndpoint extends TopicBase {
     private static Logger logger = LoggerFactory.getLogger(NoopTopicEndpoint.class);
 
     /**
-     * Network logger.
-     */
-    private static final Logger netLogger = LoggerFactoryWrapper.getNetworkLogger();
-
-    /**
      * {@inheritDoc}.
      */
     public NoopTopicEndpoint(List<String> servers, String topic) {
@@ -52,10 +48,11 @@ public abstract class NoopTopicEndpoint extends TopicBase {
     /**
      *  I/O.
      *
+     * @param type "IN" or "OUT".
      * @param message message.
-     * @return true if sucessful.
+     * @return true if successful.
      */
-    protected boolean io(String message) {
+    protected boolean io(EventType type, String message) {
 
         if (message == null || message.isEmpty()) {
             throw new IllegalArgumentException("Message is empty");
@@ -70,8 +67,7 @@ public abstract class NoopTopicEndpoint extends TopicBase {
                 this.recentEvents.add(message);
             }
 
-            netLogger.info("[OUT|{}|{}]{}{}", this.getTopicCommInfrastructure(), this.topic, System.lineSeparator(),
-                    message);
+            NetLoggerUtil.log(type, this.getTopicCommInfrastructure(), this.topic, message);
 
             broadcast(message);
         } catch (Exception e) {
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSink.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSink.java
index f6ad433d..d3745940 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSink.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSink.java
@@ -7,9 +7,9 @@
  * 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.
@@ -22,6 +22,7 @@ package org.onap.policy.common.endpoints.event.comm.bus;
 
 import java.util.List;
 import org.onap.policy.common.endpoints.event.comm.TopicSink;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
 
 /**
  * No Operation Topic Sink.
@@ -45,7 +46,7 @@ public class NoopTopicSink extends NoopTopicEndpoint implements TopicSink {
      */
     @Override
     public boolean send(String message) {
-        return super.io(message);
+        return super.io(EventType.OUT, message);
     }
 
     /**
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSource.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSource.java
index c3215e04..95ed0fe6 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSource.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/NoopTopicSource.java
@@ -22,6 +22,7 @@ package org.onap.policy.common.endpoints.event.comm.bus;
 
 import java.util.List;
 import org.onap.policy.common.endpoints.event.comm.TopicSource;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
 
 /**
  * No Operation Topic Source.
@@ -45,7 +46,7 @@ public class NoopTopicSource extends NoopTopicEndpoint implements TopicSource {
      */
     @Override
     public boolean offer(String event) {
-        return super.io(event);
+        return super.io(EventType.IN, event);
     }
 
     /**
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/InlineBusTopicSink.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/InlineBusTopicSink.java
index d6ca824e..e94bdffa 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/InlineBusTopicSink.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/InlineBusTopicSink.java
@@ -2,7 +2,7 @@
  * ============LICENSE_START=======================================================
  * policy-endpoints
  * ================================================================================
- * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
  * Modifications Copyright (C) 2018-2019 Samsung Electronics Co., Ltd.
 * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -24,7 +24,8 @@ package org.onap.policy.common.endpoints.event.comm.bus.internal;
 import java.util.UUID;
 
 import org.onap.policy.common.endpoints.event.comm.bus.BusTopicSink;
-import org.onap.policy.common.utils.slf4j.LoggerFactoryWrapper;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -39,7 +40,6 @@ public abstract class InlineBusTopicSink extends BusTopicBase implements BusTopi
      * Loggers.
      */
     private static Logger logger = LoggerFactory.getLogger(InlineBusTopicSink.class);
-    private static final Logger netLogger = LoggerFactoryWrapper.getNetworkLogger();
 
     /**
      * The partition key to publish to.
@@ -140,8 +140,7 @@ public abstract class InlineBusTopicSink extends BusTopicBase implements BusTopi
                 this.recentEvents.add(message);
             }
 
-            netLogger.info("[OUT|{}|{}]{}{}", this.getTopicCommInfrastructure(), this.topic, System.lineSeparator(),
-                    message);
+            NetLoggerUtil.log(EventType.OUT, this.getTopicCommInfrastructure(), this.topic, message);
 
             publisher.send(this.partitionId, message);
             broadcast(message);
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/SingleThreadedBusTopicSource.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/SingleThreadedBusTopicSource.java
index 83f3760b..98e30e27 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/SingleThreadedBusTopicSource.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/event/comm/bus/internal/SingleThreadedBusTopicSource.java
@@ -2,7 +2,7 @@
  * ============LICENSE_START=======================================================
  * policy-endpoints
  * ================================================================================
- * Copyright (C) 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
  * Modifications Copyright (C) 2018-2019 Samsung Electronics Co., Ltd.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -28,8 +28,9 @@ import org.onap.policy.common.endpoints.event.comm.FilterableTopicSource;
 import org.onap.policy.common.endpoints.event.comm.TopicListener;
 import org.onap.policy.common.endpoints.event.comm.bus.BusTopicSource;
 import org.onap.policy.common.endpoints.event.comm.bus.internal.BusConsumer.FilterableBusConsumer;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
 import org.onap.policy.common.utils.network.NetworkUtil;
-import org.onap.policy.common.utils.slf4j.LoggerFactoryWrapper;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -45,7 +46,6 @@ public abstract class SingleThreadedBusTopicSource extends BusTopicBase
      * that in a single file in a concise format.
      */
     private static Logger logger = LoggerFactory.getLogger(InlineBusTopicSink.class);
-    private static final Logger netLogger = LoggerFactoryWrapper.getNetworkLogger();
 
     /**
      * Bus consumer group.
@@ -228,8 +228,7 @@ public abstract class SingleThreadedBusTopicSource extends BusTopicBase
                         this.recentEvents.add(event);
                     }
 
-                    netLogger.info("[IN|{}|{}]{}{}", this.getTopicCommInfrastructure(), this.topic,
-                            System.lineSeparator(), event);
+                    NetLoggerUtil.log(EventType.IN, this.getTopicCommInfrastructure(), this.topic, event);
 
                     broadcast(event);
 
@@ -255,8 +254,7 @@ public abstract class SingleThreadedBusTopicSource extends BusTopicBase
             this.recentEvents.add(event);
         }
 
-        netLogger.info("[IN|{}|{}]{}{}", this.getTopicCommInfrastructure(), this.topic, System.lineSeparator(), event);
-
+        NetLoggerUtil.log(EventType.IN, this.getTopicCommInfrastructure(), this.topic, event);
 
         return broadcast(event);
     }
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/features/NetLoggerFeatureApi.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/features/NetLoggerFeatureApi.java
new file mode 100644
index 00000000..4e7d4444
--- /dev/null
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/features/NetLoggerFeatureApi.java
@@ -0,0 +1,62 @@
+/*
+ * ============LICENSE_START=======================================================
+ * policy-endpoints
+ * ================================================================================
+ * 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.common.endpoints.features;
+
+import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
+import org.onap.policy.common.utils.services.OrderedService;
+import org.onap.policy.common.utils.services.OrderedServiceImpl;
+import org.slf4j.Logger;
+
+/**
+ * Logging Feature API. Provides interception points before and after logging a message.
+ */
+public interface NetLoggerFeatureApi extends OrderedService {
+
+    /**
+     * Feature providers implementing this interface.
+     */
+    OrderedServiceImpl<NetLoggerFeatureApi> providers =
+                    new OrderedServiceImpl<>(NetLoggerFeatureApi.class);
+
+    /**
+     * 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/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/utils/NetLoggerUtil.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/utils/NetLoggerUtil.java
new file mode 100644
index 00000000..f82e6a8c
--- /dev/null
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/utils/NetLoggerUtil.java
@@ -0,0 +1,153 @@
+/*
+ * ============LICENSE_START=======================================================
+ * policy-endpoints
+ * ================================================================================
+ * 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.common.endpoints.utils;
+
+import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
+import org.onap.policy.common.endpoints.features.NetLoggerFeatureApi;
+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);
+    private static final Logger netLogger = 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
+    }
+
+    /**
+     * Get Network Logger.
+     *
+     * @return logger instance
+     */
+    public static Logger getNetworkLogger() {
+        return netLogger;
+    }
+
+    /**
+     * 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(netLogger, 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 = netLogger;
+        }
+
+        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) {
+        for (NetLoggerFeatureApi feature : NetLoggerFeatureApi.providers.getList()) {
+            try {
+                if (feature.beforeLog(eventLogger, type, protocol, topic, message)) {
+                    return true;
+                }
+            } catch (Exception e) {
+                logger.error("feature {} before-log failure because of {}", feature.getClass().getName(),
+                                e.getMessage(), e);
+            }
+        }
+        return false;
+    }
+
+    /**
+     * 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) {
+        for (NetLoggerFeatureApi feature : NetLoggerFeatureApi.providers.getList()) {
+            try {
+                if (feature.afterLog(eventLogger, type, protocol, topic, message)) {
+                    return true;
+                }
+            } catch (Exception e) {
+                logger.error("feature {} after-log failure because of {}", feature.getClass().getName(), e.getMessage(),
+                                e);
+            }
+        }
+        return false;
+    }
+
+}
diff --git a/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/utils/NetLoggerUtilTest.java b/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/utils/NetLoggerUtilTest.java
new file mode 100644
index 00000000..6e84c137
--- /dev/null
+++ b/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/utils/NetLoggerUtilTest.java
@@ -0,0 +1,268 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * policy-endpoints
+ * ================================================================================
+ * 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.common.endpoints.utils;
+
+import static org.junit.Assert.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.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
+import org.onap.policy.common.endpoints.features.NetLoggerFeatureApi;
+import org.onap.policy.common.endpoints.utils.NetLoggerUtil.EventType;
+import org.slf4j.Logger;
+
+/**
+ * Test class for network log utilities such as logging and feature invocation.
+ */
+public class NetLoggerUtilTest {
+
+    private static final String MESSAGE = "hello world!";
+    /**
+     * Test feature used for junits.
+     */
+    private static NetLoggerFeature netLoggerFeature;
+
+    /**
+     * Obtains the test implementation of NetLoggerFeatureApi.
+     */
+    @BeforeClass
+    public static void setUp() {
+        netLoggerFeature = (NetLoggerFeature) NetLoggerFeatureApi.providers.getList().get(0);
+    }
+
+    /**
+     * Clears events list and resets return/exceptions flags before invoking every unit test.
+     */
+    @Before
+    public void reset() {
+        TestAppender.clear();
+        netLoggerFeature.setReturnValue(false, false);
+        netLoggerFeature.setExceptions(false, false);
+    }
+
+    /**
+     * Tests obtaining the network logger instance.
+     */
+    @Test
+    public void getNetworkLoggerTest() {
+        assertEquals("network", NetLoggerUtil.getNetworkLogger().getName());
+    }
+
+    /**
+     * Tests logging a message to the network logger and invoking features before/after logging.
+     */
+    @Test
+    public 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
+    public 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
+    public 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
+    public 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
+    public 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
+    public 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.
+         */
+        public static 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/policy-endpoints/src/test/resources/META-INF/services/org.onap.policy.common.endpoints.features.NetLoggerFeatureApi b/policy-endpoints/src/test/resources/META-INF/services/org.onap.policy.common.endpoints.features.NetLoggerFeatureApi
new file mode 100644
index 00000000..c861ad18
--- /dev/null
+++ b/policy-endpoints/src/test/resources/META-INF/services/org.onap.policy.common.endpoints.features.NetLoggerFeatureApi
@@ -0,0 +1 @@
+org.onap.policy.common.endpoints.utils.NetLoggerUtilTest$NetLoggerFeature
diff --git a/policy-endpoints/src/test/resources/logback-test.xml b/policy-endpoints/src/test/resources/logback-test.xml
index b3feef90..4edcc9db 100644
--- a/policy-endpoints/src/test/resources/logback-test.xml
+++ b/policy-endpoints/src/test/resources/logback-test.xml
@@ -2,7 +2,7 @@
   ============LICENSE_START=======================================================
   ONAP
   ================================================================================
-  Copyright (C) 2018 AT&T Intellectual Property. All rights reserved.
+  Copyright (C) 2018-2019 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.
@@ -27,8 +27,14 @@
         </encoder>
     </appender>
     
+    <appender name="testAppender" class="org.onap.policy.common.endpoints.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>
diff --git a/utils/src/main/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapper.java b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedService.java
index 6f800015..c5050c83 100644
--- a/utils/src/main/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapper.java
+++ b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedService.java
@@ -1,9 +1,8 @@
 /*
  * ============LICENSE_START=======================================================
- * ONAP Policy Engine - Common Modules
+ * utils
  * ================================================================================
- * Copyright (C) 2019 Samsung Electronics. All rights reserved.
- * Modifications Copyright (C) 2019 AT&T Intellectual Property.
+ * 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.
@@ -19,29 +18,30 @@
  * ============LICENSE_END=========================================================
  */
 
-package org.onap.policy.common.utils.slf4j;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+package org.onap.policy.common.utils.services;
 
 /**
- * Helper class to retrieve particular types of loggers without storing the logger name everywhere in ths code.
+ * This is a base interface that is used to control the order of a list
+ * of services (features) discovered via 'ServiceLoader'. See
+ * 'OrderedServiceImpl' for more details.
  */
-public class LoggerFactoryWrapper {
-
+@FunctionalInterface
+public interface OrderedService {
     /**
-     * Constructs the object.
+     * Get sequence number.
+     *
+     * @return an integer sequence number, which determines the order of a list
+     *     of objects implementing this interface
      */
-    private LoggerFactoryWrapper() {
-        super();
-    }
+    public int getSequenceNumber();
+
 
     /**
-     * Get Network Logger.
+     * Get the name.
      *
-     * @return logger instance
+     * @return the name of the ordered service
      */
-    public static Logger getNetworkLogger() {
-        return LoggerFactory.getLogger("network");
+    public default String getName() {
+        return this.getClass().getName();
     }
 }
diff --git a/utils/src/main/java/org/onap/policy/common/utils/services/OrderedServiceImpl.java b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedServiceImpl.java
new file mode 100644
index 00000000..bbd30220
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/services/OrderedServiceImpl.java
@@ -0,0 +1,135 @@
+/*
+ * ============LICENSE_START=======================================================
+ * utils
+ * ================================================================================
+ * 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.common.utils.services;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.ServiceLoader;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class is a template for building a sorted list of service instances,
+ * which are discovered and created using 'ServiceLoader'. 
+ */
+public class OrderedServiceImpl<T extends OrderedService> {
+    // logger
+    private static Logger  logger = LoggerFactory.getLogger(OrderedServiceImpl.class); 
+
+    // sorted list of instances implementing the service
+    private List<T> implementers = null;
+
+    // 'ServiceLoader' that is used to discover and create the services
+    private ServiceLoader<T> serviceLoader = null;
+
+    // use this to ensure that we only use one unique instance of each class
+    @SuppressWarnings("rawtypes")
+    private static HashMap<Class,OrderedService> classToSingleton = new HashMap<>();
+
+    /**
+     * Constructor - create the 'ServiceLoader' instance.
+     *
+     * @param clazz the class object associated with 'T' (I supposed it could
+     *     be a subclass, but I'm not sure this is useful)
+     */
+    public OrderedServiceImpl(Class<T> clazz) {
+        // This constructor wouldn't be needed if 'T.class' was legal
+        serviceLoader = ServiceLoader.load(clazz);
+    }
+
+    /**
+     * Get List of implementers.
+     * 
+     * @return the sorted list of services implementing interface 'T' discovered
+     *     by 'ServiceLoader'.
+     */
+    public synchronized List<T> getList() {
+        if (implementers == null) {
+            rebuildList();
+        }
+        return implementers;
+    }
+
+    /**
+     * This method is called by 'getList', but could also be called directly if
+     * we were running with a 'ClassLoader' that supported the dynamic addition
+     * of JAR files. In this case, it could be invoked in order to discover any
+     * new services implementing interface 'T'. This is probably a relatively
+     * expensive operation in terms of CPU and elapsed time, so it is best if it
+     * isn't invoked too frequently.
+     *
+     * @return the sorted list of services implementing interface 'T' discovered
+     *      by 'ServiceLoader'.
+     */
+    @SuppressWarnings("unchecked")
+    public synchronized List<T> rebuildList() {
+        // build a list of all of the current implementors
+        List<T> tmp = new LinkedList<>();
+        for (T service : serviceLoader) {
+            tmp.add((T)getSingleton(service));
+        }
+
+        // Sort the list according to sequence number, and then alphabetically
+        // according to full class name.
+        Collections.sort(tmp, (o1, o2) -> {
+            int s1 = o1.getSequenceNumber();
+            int s2 = o2.getSequenceNumber();
+            if (s1 < s2) {
+                return -1;
+            } else if (s1 > s2) {
+                return 1;
+            } else {
+                return o1.getClass().getName().compareTo(o2.getClass().getName());
+            }
+        });
+
+        // create an unmodifiable version of this list
+        implementers = Collections.unmodifiableList(tmp);
+        logger.info("***** OrderedServiceImpl implementers:\n {}", implementers);
+        return implementers;
+    }
+
+    /**
+     * If a service implements multiple APIs managed by 'ServiceLoader', a
+     * separate instance is created for each API. This method ensures that
+     * the first instance is used in all of the lists.
+     *
+     * @param service this is the object created by ServiceLoader
+     * @return the object to use in place of 'service'. If 'service' is the first
+     *     object of this class created by ServiceLoader, it is returned. If not,
+     *     the object of this class that was initially created is returned
+     *     instead.
+     */
+    private static synchronized OrderedService getSingleton(OrderedService service) {
+        // see if we already have an instance of this class
+        OrderedService rval = classToSingleton.get(service.getClass());
+        if (rval == null) {
+            // No previous instance of this class exists -- use the supplied
+            // instance, and place it in the table.
+            rval = service;
+            classToSingleton.put(service.getClass(), service);
+        }
+        return rval;
+    }
+}
diff --git a/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java b/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java
index eb918d35..e5a79bc3 100644
--- a/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java
+++ b/utils/src/test/java/org/onap/policy/common/utils/resources/ResourceUtilsTest.java
@@ -250,7 +250,9 @@ public class ResourceUtilsTest {
         assertNull(theString);
 
         theString = ResourceUtils.getResourceAsString("");
-        assertEquals("logback-test.xml\norg\ntestdir\n", theString);
+
+        assertEquals("logback-test.xml\nMETA-INF\norg\ntestdir\n", theString);
+
     }
 
     @Test
diff --git a/utils/src/test/java/org/onap/policy/common/utils/services/OrderedServiceImplTest.java b/utils/src/test/java/org/onap/policy/common/utils/services/OrderedServiceImplTest.java
new file mode 100644
index 00000000..39c8a2be
--- /dev/null
+++ b/utils/src/test/java/org/onap/policy/common/utils/services/OrderedServiceImplTest.java
@@ -0,0 +1,205 @@
+/*
+ * ============LICENSE_START=======================================================
+ * utils
+ * ================================================================================
+ * 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.common.utils.services;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class OrderedServiceImplTest {
+
+    private static final int HIGH_PRIORITY_NUM = -1000;
+    private static final int LOW_PRIORITY_NUM = 1000;
+
+    private static GenericService highPrioService;
+    private static GenericService lowPrioService;
+
+    /**
+     * Saves the original state of the ordered service list to restore after each test.
+     */
+    @BeforeClass
+    public static void setup() {
+        List<GenericService> implementers = GenericService.providers.getList();
+        highPrioService = implementers.get(0);
+        lowPrioService = implementers.get(1);
+    }
+
+    /**
+     * Restores original state after each test.
+     */
+    @Before
+    public void resetOrder() {
+        highPrioService.setSequenceNumber(HIGH_PRIORITY_NUM);
+        lowPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+    }
+
+    /**
+     * Tests obtaining a list of service implementers.
+     */
+    @Test
+    public void getListTest() {
+        List<GenericService> implementers = GenericService.providers.getList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+    }
+
+    /**
+     * Tests inverting the priority of two services to ensure the list is rebuilt
+     * with the new order.
+     */
+    @Test
+    public void rebuildListInvertedPriorityTest() {
+
+        List<GenericService> implementers = GenericService.providers.getList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+        highPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+        lowPrioService.setSequenceNumber(HIGH_PRIORITY_NUM);
+
+        implementers = GenericService.providers.rebuildList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(lowPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+        assertEquals(highPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+    }
+
+    /**
+     * Tests that the service list is ordered alphabetically by class names
+     * if the priorities are equivalent.
+     */
+    @Test
+    public void rebuildListEqualPriorityTest() {
+
+        List<GenericService> implementers = GenericService.providers.getList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(HIGH_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+        highPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+        lowPrioService.setSequenceNumber(LOW_PRIORITY_NUM);
+
+        implementers = GenericService.providers.rebuildList();
+        assertEquals(2, implementers.size());
+
+        assertEquals(highPrioService, implementers.get(0));
+        assertEquals(LOW_PRIORITY_NUM, highPrioService.getSequenceNumber());
+
+        assertEquals(lowPrioService, implementers.get(1));
+        assertEquals(LOW_PRIORITY_NUM, lowPrioService.getSequenceNumber());
+
+    }
+
+    /**
+     * Test interface that extends OrderedService to allow changing the sequence number.
+     */
+    public static interface GenericService extends OrderedService {
+
+        /**
+         * Providers of the GenericService interface.
+         */
+        OrderedServiceImpl<GenericService> providers = new OrderedServiceImpl<>(GenericService.class);
+
+        /**
+         * Sets the sequence number of the service.
+         */
+        public void setSequenceNumber(int seqNum);
+
+    }
+
+    /**
+     * A high priority service class.
+     */
+    public static class HighPriorityService implements GenericService {
+
+        /**
+         * Defaults to a high priority.
+         */
+        private int seqNum = HIGH_PRIORITY_NUM;
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public int getSequenceNumber() {
+            return this.seqNum;
+        }
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public void setSequenceNumber(int seqNum) {
+            this.seqNum = seqNum;
+        }
+
+    }
+
+    /**
+     * A low priority service class.
+     */
+    public static class LowPriorityService implements GenericService {
+
+        /**
+         * Defaults to a low priority.
+         */
+        private int seqNum = LOW_PRIORITY_NUM;
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public int getSequenceNumber() {
+            return this.seqNum;
+        }
+
+        /**
+         * {@inheritDoc}.
+         */
+        @Override
+        public void setSequenceNumber(int seqNum) {
+            this.seqNum = seqNum;
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/utils/src/test/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapperTest.java b/utils/src/test/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapperTest.java
deleted file mode 100644
index 4bf8db30..00000000
--- a/utils/src/test/java/org/onap/policy/common/utils/slf4j/LoggerFactoryWrapperTest.java
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * ============LICENSE_START=======================================================
- * ONAP Policy Engine - Common Modules
- * ================================================================================
- * Copyright (C) 2019 Samsung Electronics. All rights reserved.
- * Modifications Copyright (C) 2019 AT&T Intellectual Property.
- * ================================================================================
- * 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.utils.slf4j;
-
-import static org.junit.Assert.assertSame;
-import static org.mockito.Mockito.mock;
-
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import org.powermock.api.mockito.PowerMockito;
-import org.powermock.core.classloader.annotations.PrepareForTest;
-import org.powermock.modules.junit4.PowerMockRunner;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-
-@RunWith(PowerMockRunner.class)
-@PrepareForTest(LoggerFactory.class)
-public class LoggerFactoryWrapperTest {
-    @Test
-    public void test_get_network_logger() {
-        String netLoggerName = "network";
-        Logger mockLogger = mock(Logger.class);
-
-        PowerMockito.mockStatic(LoggerFactory.class);
-
-        PowerMockito.when(LoggerFactory.getLogger(netLoggerName)).thenReturn(mockLogger);
-        assertSame(mockLogger, LoggerFactoryWrapper.getNetworkLogger());
-    }
-}
diff --git a/utils/src/test/resources/META-INF/services/org.onap.policy.common.utils.services.OrderedServiceImplTest$GenericService b/utils/src/test/resources/META-INF/services/org.onap.policy.common.utils.services.OrderedServiceImplTest$GenericService
new file mode 100644
index 00000000..1e920f46
--- /dev/null
+++ b/utils/src/test/resources/META-INF/services/org.onap.policy.common.utils.services.OrderedServiceImplTest$GenericService
@@ -0,0 +1,2 @@
+org.onap.policy.common.utils.services.OrderedServiceImplTest$HighPriorityService
+org.onap.policy.common.utils.services.OrderedServiceImplTest$LowPriorityService
\ No newline at end of file