Add JUnit for engine service

Although the Apex engine service is called by the policy engine
tests and the various interface tests, the test coverage on these
classes is not showing up in Sonar. In any event it is better
that specific JUint is done for them.

Issue-ID: POLICY-1034
Change-Id: I0028c7e5e870c18649870536cf3691fce2ab689c
Signed-off-by: liamfallon <liam.fallon@ericsson.com>

2 files changed, 111 insertions, 78 deletions

diff --git a/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineServiceImpl.java b/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineServiceImpl.java
index c99987542..ee1a5dcdf 100644
--- a/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineServiceImpl.java
+++ b/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineServiceImpl.java
@@ -66,6 +66,7 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     // Recurring string constants
     private static final String ENGINE_KEY_PREAMBLE = "engine with key ";
     private static final String NOT_FOUND_SUFFIX = " not found in engine service";
+    private static final String ENGINE_KEY_NOT_SPECIFIED = "engine key must be specified and may not be null";
 
     // Constants for timing
     private static final long MAX_START_WAIT_TIME = 5000; // 5 seconds
@@ -95,23 +96,17 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
      * constructor is private to prevent subclassing.
      *
      * @param engineServiceKey the engine service key
-     * @param incomingThreadCount the thread count, the number of engine workers to start
+     * @param threadCount the thread count, the number of engine workers to start
      * @param periodicEventPeriod the period in milliseconds at which periodic events are generated
      * @throws ApexException on worker instantiation errors
      */
-    private EngineServiceImpl(final AxArtifactKey engineServiceKey, final int incomingThreadCount,
+    private EngineServiceImpl(final AxArtifactKey engineServiceKey, final int threadCount,
                     final long periodicEventPeriod) {
-        LOGGER.entry(engineServiceKey, incomingThreadCount);
+        LOGGER.entry(engineServiceKey, threadCount);
 
         this.engineServiceKey = engineServiceKey;
         this.periodicEventPeriod = periodicEventPeriod;
 
-        int threadCount = incomingThreadCount;
-        if (threadCount <= 0) {
-            // Just start one engine worker
-            threadCount = 1;
-        }
-
         // Start engine workers
         for (int engineCounter = 0; engineCounter < threadCount; engineCounter++) {
             final AxArtifactKey engineWorkerKey = new AxArtifactKey(engineServiceKey.getName() + '-' + engineCounter,
@@ -137,22 +132,18 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     public static EngineServiceImpl create(final EngineServiceParameters config) throws ApexException {
         if (config == null) {
             LOGGER.warn("Engine service configuration parameters is null");
-            throw new ApexException("engine service configuration parameters is null");
+            throw new ApexException("engine service configuration parameters are null");
         }
+        
         final GroupValidationResult validation = config.validate();
         if (!validation.isValid()) {
             LOGGER.warn("Invalid engine service configuration parameters: {}" + validation.getResult());
             throw new ApexException("Invalid engine service configuration parameters: " + validation);
         }
+        
         final AxArtifactKey engineServiceKey = config.getEngineKey();
         final int threadCount = config.getInstanceCount();
 
-        // Check if the Apex model specified is sane
-        if (engineServiceKey == null) {
-            LOGGER.warn("engine service key is null");
-            throw new ApexException("engine service key is null");
-        }
-
         return new EngineServiceImpl(engineServiceKey, threadCount, config.getPeriodicEventPeriod());
     }
 
@@ -166,6 +157,18 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     public void registerActionListener(final String listenerName, final ApexEventListener apexEventListener) {
         LOGGER.entry(apexEventListener);
 
+        if (listenerName == null) {
+            String message = "listener name must be specified and may not be null";
+            LOGGER.warn(message);
+            return;
+        }
+
+        if (apexEventListener == null) {
+            String message = "apex event listener must be specified and may not be null";
+            LOGGER.warn(message);
+            return;
+        }
+
         // Register the Apex event listener on all engine workers, each worker will return Apex
         // events to the listening application
         for (final EngineService engineWorker : engineWorkerMap.values()) {
@@ -248,6 +251,13 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     @Override
     public void updateModel(final AxArtifactKey incomingEngineServiceKey, final String apexModelString,
                     final boolean forceFlag) throws ApexException {
+        // Check if the engine service key specified is sane
+        if (incomingEngineServiceKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            throw new ApexException(message);
+        }
+
         // Check if the Apex model specified is sane
         if (apexModelString == null || apexModelString.trim().length() == 0) {
             String emptyModelMessage = "model for updating engine service with key "
@@ -267,12 +277,6 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
             throw new ApexException(message, e);
         }
 
-        if (apexPolicyModel == null) {
-            String message = "apex model null on engine service " + incomingEngineServiceKey.getId();
-            LOGGER.error(message);
-            throw new ApexException(message);
-        }
-
         // Update the model
         updateModel(incomingEngineServiceKey, apexPolicyModel, forceFlag);
 
@@ -290,6 +294,13 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
                     final boolean forceFlag) throws ApexException {
         LOGGER.entry(incomingEngineServiceKey);
 
+        // Check if the engine service key specified is sane
+        if (incomingEngineServiceKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            throw new ApexException(message);
+        }
+
         // Check if the Apex model specified is sane
         if (apexModel == null) {
             LOGGER.warn("model for updating on engine service with key " + incomingEngineServiceKey.getId()
@@ -315,6 +326,22 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
             }
         }
 
+        executeModelUpdate(incomingEngineServiceKey, apexModel, forceFlag);
+
+        LOGGER.exit();
+    }
+
+    /**
+     * Execute the model update on the engine instances.
+     * 
+     * @param incomingEngineServiceKey the engine service key to update
+     * @param apexModel the model to update the engines with
+     * @param forceFlag if true, ignore compatibility problems
+     * @throws ApexException on model update errors
+     */
+    private void executeModelUpdate(final AxArtifactKey incomingEngineServiceKey, final AxPolicyModel apexModel,
+                    final boolean forceFlag) throws ApexException {
+        
         if (!isStopped()) {
             stopEngines(incomingEngineServiceKey);
         }
@@ -349,8 +376,6 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
             LOGGER.warn(errorString);
             throw new ApexException(errorString);
         }
-
-        LOGGER.exit();
     }
 
     /**
@@ -432,11 +457,6 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
         for (final EngineService engine : engineWorkerMap.values()) {
             start(engine.getKey());
         }
-
-        // Check if periodic events should be turned on
-        if (periodicEventPeriod > 0) {
-            startPeriodicEvents(periodicEventPeriod);
-        }
     }
 
     /*
@@ -449,6 +469,12 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     public void start(final AxArtifactKey engineKey) throws ApexException {
         LOGGER.entry(engineKey);
 
+        if (engineKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            throw new ApexException(message);
+        }
+
         // Check if we have this key on our map
         if (!engineWorkerMap.containsKey(engineKey)) {
             String message = ENGINE_KEY_PREAMBLE + engineKey.getId() + NOT_FOUND_SUFFIX;
@@ -458,6 +484,11 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
 
         // Start the engine
         engineWorkerMap.get(engineKey).start(engineKey);
+        
+        // Check if periodic events should be turned on
+        if (periodicEventPeriod > 0) {
+            startPeriodicEvents(periodicEventPeriod);
+        }
 
         LOGGER.exit(engineKey);
     }
@@ -471,6 +502,11 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     public void stop() throws ApexException {
         LOGGER.entry();
 
+        if (periodicEventGenerator != null) {
+            periodicEventGenerator.cancel();
+            periodicEventGenerator = null;
+        }
+        
         // Stop each engine
         for (final EngineService engine : engineWorkerMap.values()) {
             if (engine.getState() != AxEngineState.STOPPED) {
@@ -491,6 +527,12 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     public void stop(final AxArtifactKey engineKey) throws ApexException {
         LOGGER.entry(engineKey);
 
+        if (engineKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            throw new ApexException(message);
+        }
+
         // Check if we have this key on our map
         if (!engineWorkerMap.containsKey(engineKey)) {
             LOGGER.warn(ENGINE_KEY_PREAMBLE + engineKey.getId() + NOT_FOUND_SUFFIX);
@@ -532,6 +574,12 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
     public void clear(final AxArtifactKey engineKey) throws ApexException {
         LOGGER.entry(engineKey);
 
+        if (engineKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            throw new ApexException(message);
+        }
+
         // Check if we have this key on our map
         if (!engineWorkerMap.containsKey(engineKey)) {
             LOGGER.warn(ENGINE_KEY_PREAMBLE + engineKey.getId() + NOT_FOUND_SUFFIX);
@@ -570,9 +618,16 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
      */
     @Override
     public boolean isStarted(final AxArtifactKey engineKey) {
+        if (engineKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            return false;
+        }
+
         // Check if we have this key on our map
         if (!engineWorkerMap.containsKey(engineKey)) {
             LOGGER.warn(ENGINE_KEY_PREAMBLE + engineKey.getId() + NOT_FOUND_SUFFIX);
+            return false;
         }
         return engineWorkerMap.get(engineKey).isStarted();
     }
@@ -601,9 +656,16 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
      */
     @Override
     public boolean isStopped(final AxArtifactKey engineKey) {
+        if (engineKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            return true;
+        }
+
         // Check if we have this key on our map
         if (!engineWorkerMap.containsKey(engineKey)) {
             LOGGER.warn(ENGINE_KEY_PREAMBLE + engineKey.getId() + NOT_FOUND_SUFFIX);
+            return true;
         }
         return engineWorkerMap.get(engineKey).isStopped();
     }
@@ -647,6 +709,7 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
         // Stop periodic events
         periodicEventGenerator.cancel();
         periodicEventGenerator = null;
+        periodicEventPeriod = 0;
     }
 
     /*
@@ -657,6 +720,12 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
      */
     @Override
     public String getStatus(final AxArtifactKey engineKey) throws ApexException {
+        if (engineKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            throw new ApexException(message);
+        }
+
         // Check if we have this key on our map
         if (!engineWorkerMap.containsKey(engineKey)) {
             LOGGER.warn(ENGINE_KEY_PREAMBLE + engineKey.getId() + NOT_FOUND_SUFFIX);
@@ -675,6 +744,12 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
      */
     @Override
     public String getRuntimeInfo(final AxArtifactKey engineKey) throws ApexException {
+        if (engineKey == null) {
+            String message = ENGINE_KEY_NOT_SPECIFIED;
+            LOGGER.warn(message);
+            throw new ApexException(message);
+        }
+
         // Check if we have this key on our map
         if (!engineWorkerMap.containsKey(engineKey)) {
             LOGGER.warn(ENGINE_KEY_PREAMBLE + engineKey.getId() + NOT_FOUND_SUFFIX);
@@ -693,6 +768,11 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
      */
     @Override
     public void sendEvent(final ApexEvent event) {
+        if (event == null) {
+            LOGGER.warn("Null events cannot be processed, in engine service " + engineServiceKey.getId());
+            return;
+        }
+
         // Check if we have this key on our map
         if (getState() == AxEngineState.STOPPED) {
             LOGGER.warn("event " + event.getName() + " not processed, no engines on engine service "
@@ -700,11 +780,6 @@ public final class EngineServiceImpl implements EngineService, EngineServiceEven
             return;
         }
 
-        if (event == null) {
-            LOGGER.warn("Null events cannot be processed, in engine service " + engineServiceKey.getId());
-            return;
-        }
-
         if (DEBUG_ENABLED) {
             LOGGER.debug("Forwarding Apex Event {} to the processing engine", event);
         }
diff --git a/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineWorker.java b/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineWorker.java
index 56b3b84c4..a7d179959 100644
--- a/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineWorker.java
+++ b/services/services-engine/src/main/java/org/onap/policy/apex/service/engine/runtime/impl/EngineWorker.java
@@ -76,7 +76,6 @@ final class EngineWorker implements EngineService {
     private static final XLogger LOGGER = XLoggerFactory.getXLogger(EngineService.class);
 
     // Recurring string constants
-    private static final String IS_NULL_SUFFIX = " is  null";
     private static final String ENGINE_FOR_KEY_PREFIX = "apex engine for engine key ";
     private static final String ENGINE_SUFFIX = " of this engine";
     private static final String BAD_KEY_MATCH_TAG = " does not match the key";
@@ -108,7 +107,7 @@ final class EngineWorker implements EngineService {
      * @param threadFactory the thread factory to use for creating the event processing thread
      * @throws ApexException thrown on errors on worker instantiation
      */
-    EngineWorker(final AxArtifactKey engineWorkerKey, final BlockingQueue<ApexEvent> queue,
+    protected EngineWorker(final AxArtifactKey engineWorkerKey, final BlockingQueue<ApexEvent> queue,
             final ApplicationThreadFactory threadFactory) {
         LOGGER.entry(engineWorkerKey);
 
@@ -136,13 +135,6 @@ final class EngineWorker implements EngineService {
      */
     @Override
     public void registerActionListener(final String listenerName, final ApexEventListener apexEventListener) {
-        // Sanity checks on the Apex model
-        if (engine == null) {
-            LOGGER.warn("listener registration on engine with key " + engineWorkerKey.getId()
-                    + ", failed, listener is null");
-            return;
-        }
-
         engine.addEventListener(listenerName, new EnEventListenerImpl(apexEventListener, apexEnEventConverter));
     }
 
@@ -155,13 +147,6 @@ final class EngineWorker implements EngineService {
      */
     @Override
     public void deregisterActionListener(final String listenerName) {
-        // Sanity checks on the Apex model
-        if (engine == null) {
-            LOGGER.warn("listener deregistration on engine with key " + engineWorkerKey.getId()
-                    + ", failed, listener is null");
-            return;
-        }
-
         engine.removeEventListener(listenerName);
     }
 
@@ -233,11 +218,6 @@ final class EngineWorker implements EngineService {
             throw new ApexException("failed to unmarshal the apex model on engine " + engineKey.getId(), e);
         }
 
-        if (apexPolicyModel == null) {
-            LOGGER.error("apex model null on engine " + engineKey.getId());
-            throw new ApexException("apex model null on engine " + engineKey.getId());
-        }
-
         // Update the Apex model in the Apex engine
         updateModel(engineKey, apexPolicyModel, forceFlag);
 
@@ -265,12 +245,6 @@ final class EngineWorker implements EngineService {
             throw new ApexException(message);
         }
 
-        // Sanity checks on the Apex model
-        if (engine == null) {
-            LOGGER.warn("engine with key " + engineKey.getId() + " not initialized");
-            throw new ApexException("engine with key " + engineKey.getId() + " not initialized");
-        }
-
         // Check model compatibility
         if (ModelService.existsModel(AxPolicyModel.class)) {
             // The current policy model may or may not be defined
@@ -336,12 +310,6 @@ final class EngineWorker implements EngineService {
                     + engineWorkerKey.getId() + ENGINE_SUFFIX);
         }
 
-        if (engine == null) {
-            String message = ENGINE_FOR_KEY_PREFIX + engineWorkerKey.getId() + " is null";
-            LOGGER.error(message);
-            throw new ApexException(message);
-        }
-
         // Starts the event processing thread that handles incoming events
         if (processorThread != null && processorThread.isAlive()) {
             String message = ENGINE_FOR_KEY_PREFIX + engineWorkerKey.getId() + " is already running with state "
@@ -387,12 +355,6 @@ final class EngineWorker implements EngineService {
                     + engineWorkerKey.getId() + ENGINE_SUFFIX);
         }
 
-        if (engine == null) {
-            String message = ENGINE_FOR_KEY_PREFIX + engineWorkerKey.getId() + " is null";
-            LOGGER.error(message);
-            throw new ApexException(message);
-        }
-
         // Interrupt the worker to stop its thread
         if (processorThread == null || !processorThread.isAlive()) {
             processorThread = null;
@@ -439,11 +401,6 @@ final class EngineWorker implements EngineService {
                     + engineWorkerKey.getId() + ENGINE_SUFFIX);
         }
 
-        if (engine == null) {
-            LOGGER.error(ENGINE_FOR_KEY_PREFIX + engineWorkerKey.getId() + IS_NULL_SUFFIX);
-            throw new ApexException(ENGINE_FOR_KEY_PREFIX + engineWorkerKey.getId() + IS_NULL_SUFFIX);
-        }
-
         // Interrupt the worker to stop its thread
         if (processorThread != null && !processorThread.isAlive()) {
             LOGGER.warn(ENGINE_FOR_KEY_PREFIX + engineWorkerKey.getId() + " is not stopped with state "
@@ -562,6 +519,7 @@ final class EngineWorker implements EngineService {
         try {
             final ByteArrayOutputStream baOutputStream = new ByteArrayOutputStream();
             final ApexModelWriter<AxEngineModel> modelWriter = new ApexModelWriter<>(AxEngineModel.class);
+            modelWriter.setJsonOutput(true);
             modelWriter.write(apexEngineModel, baOutputStream);
             return baOutputStream.toString();
         } catch (final Exception e) {