Retaining context in APEX Engine based on policies received in PdpUpdate

Change-Id: I73fad5bf76ed6b4979f5ab76013f204ea82da30b
Issue-ID: POLICY-2215
Signed-off-by: a.sreekumar <ajith.sreekumar@est.tech>

6 files changed, 125 insertions, 266 deletions

diff --git a/core/core-engine/pom.xml b/core/core-engine/pom.xml
index fff6d528c..b86fd50ec 100644
--- a/core/core-engine/pom.xml
+++ b/core/core-engine/pom.xml
@@ -63,6 +63,11 @@
             <artifactId>mockito-all</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <profiles>
diff --git a/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/context/ApexInternalContext.java b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/context/ApexInternalContext.java
index 3d6a72451..0589e8311 100644
--- a/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/context/ApexInternalContext.java
+++ b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/context/ApexInternalContext.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ *  Modifications 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.
@@ -21,14 +22,12 @@
 package org.onap.policy.apex.core.engine.context;
 
 import com.google.common.collect.Maps;
-
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.NavigableMap;
 import java.util.Set;
 import java.util.TreeMap;
-
 import org.onap.policy.apex.context.ContextAlbum;
 import org.onap.policy.apex.context.ContextException;
 import org.onap.policy.apex.context.Distributor;
@@ -113,13 +112,24 @@ public class ApexInternalContext implements AxConceptGetter<ContextAlbum> {
      * in the new model.
      *
      * @param newPolicyModel The new incoming Apex model to use for context
+     * @param isSubsequentInstance if the current worker instance being updated is not the first one
      * @throws ContextException On errors on context setting
      */
-    public void update(final AxPolicyModel newPolicyModel) throws ContextException {
+    public void update(final AxPolicyModel newPolicyModel, boolean isSubsequentInstance) throws ContextException {
         if (newPolicyModel == null) {
             throw new ContextException("internal context update failed, supplied model is null");
         }
-
+        // context is shared between all the engine instances
+        // during model update context album only needs to be updated for the first instance.
+        // remaining engine instances can just copy the context
+        if (isSubsequentInstance) {
+            contextAlbums.clear();
+            for (AxArtifactKey contextAlbumKey : ModelService.getModel(AxContextAlbums.class).getAlbumsMap().keySet()) {
+                contextAlbums.put(contextAlbumKey, contextDistributor.createContextAlbum(contextAlbumKey));
+            }
+            key = newPolicyModel.getKey();
+            return;
+        }
         // Get the differences between the existing context and the new context
         final KeyedMapDifference<AxArtifactKey, AxContextAlbum> contextDifference =
                 new ContextComparer().compare(ModelService.getModel(AxContextAlbums.class), newPolicyModel.getAlbums());
@@ -143,11 +153,11 @@ public class ApexInternalContext implements AxConceptGetter<ContextAlbum> {
                         + newContextAlbum.getItemSchema().getId() + "\" on incoming model");
             }
         }
-        
+
         // Remove maps that are no longer used
         for (final Entry<AxArtifactKey, AxContextAlbum> removedContextAlbumEntry : contextDifference.getLeftOnly()
                 .entrySet()) {
-            contextDistributor.removeContextAlbum(removedContextAlbumEntry.getValue());
+            contextDistributor.removeContextAlbum(removedContextAlbumEntry.getKey());
             contextAlbums.remove(removedContextAlbumEntry.getKey());
         }
 
@@ -156,6 +166,11 @@ public class ApexInternalContext implements AxConceptGetter<ContextAlbum> {
 
         // Set up the new context albums
         for (final AxArtifactKey contextAlbumKey : contextDifference.getRightOnly().keySet()) {
+            // In case if a context album is part of previous and current model, but needs to be cleared
+            // for example, due to a major version change
+            if (contextAlbums.containsKey(contextAlbumKey)) {
+                contextDistributor.removeContextAlbum(contextAlbumKey);
+            }
             contextAlbums.put(contextAlbumKey, contextDistributor.createContextAlbum(contextAlbumKey));
         }
 
diff --git a/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/ApexEngine.java b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/ApexEngine.java
index 2c5167d1b..4c4166380 100644
--- a/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/ApexEngine.java
+++ b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/ApexEngine.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ *  Modifications 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.
@@ -21,7 +22,6 @@
 package org.onap.policy.apex.core.engine.engine;
 
 import java.util.Map;
-
 import org.onap.policy.apex.core.engine.event.EnEvent;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
@@ -49,9 +49,10 @@ public interface ApexEngine {
      * transferred if there is common context in the old and new models.
      *
      * @param apexModel the apex model
+     * @param isSubsequentInstance if the current worker instance being updated is not the first one
      * @throws ApexException on model update errors
      */
-    void updateModel(AxPolicyModel apexModel) throws ApexException;
+    void updateModel(AxPolicyModel apexModel, boolean isSubsequentInstance) throws ApexException;
 
     /**
      * Starts an Apex engine so that it can receive events.
diff --git a/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImpl.java b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImpl.java
index 87ce1230e..9cbd2050f 100644
--- a/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImpl.java
+++ b/core/core-engine/src/main/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImpl.java
@@ -26,7 +26,6 @@ import static org.onap.policy.common.utils.validation.Assertions.argumentNotNull
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Map.Entry;
-
 import org.onap.policy.apex.context.ContextAlbum;
 import org.onap.policy.apex.context.ContextException;
 import org.onap.policy.apex.core.engine.context.ApexInternalContext;
@@ -105,7 +104,7 @@ public class ApexEngineImpl implements ApexEngine {
      * {@inheritDoc}.
      */
     @Override
-    public void updateModel(final AxPolicyModel apexModel) throws ApexException {
+    public void updateModel(final AxPolicyModel apexModel, final boolean isSubsequentInstance) throws ApexException {
         if (apexModel != null) {
             LOGGER.entry("updateModel()->" + key.getId() + ", apexPolicyModel=" + apexModel.getKey().getId());
         } else {
@@ -125,8 +124,8 @@ public class ApexEngineImpl implements ApexEngine {
                 /// New internal context
                 internalContext = new ApexInternalContext(apexModel);
             } else {
-                // Exiting internal context which must be updated
-                internalContext.update(apexModel);
+                // Existing internal context which must be updated
+                internalContext.update(apexModel, isSubsequentInstance);
             }
         } catch (final ContextException e) {
             LOGGER.warn(UPDATE_MODEL + key.getId() + ", error setting the context for engine \"" + key.getId() + "\"",
diff --git a/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/context/ApexInternalContextTest.java b/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/context/ApexInternalContextTest.java
index a75ad37f6..3d0d377bf 100644
--- a/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/context/ApexInternalContextTest.java
+++ b/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/context/ApexInternalContextTest.java
@@ -1,25 +1,27 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications 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.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.core.engine.context;
 
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
@@ -156,33 +158,23 @@ public class ApexInternalContextTest {
     @Test
     public void testAlbumUpdate() throws ContextException {
         ApexInternalContext context = new ApexInternalContext(policyModel);
-
-        try {
-            context.update(null);
-            fail("test should throw an exception");
-        } catch (ContextException ce) {
-            assertEquals("internal context update failed, supplied model is null", ce.getMessage());
-        }
+        assertThatThrownBy(() -> context.update(null, false))
+            .hasMessage("internal context update failed, supplied model is null");
 
         assertEquals(policyModel.getKey().getId(), context.getKey().getId());
         assertEquals(1, context.getContextAlbums().size());
 
-        try {
-            context.update(incompatiblePolicyModel);
-            fail("test should throw an exception here");
-        } catch (ContextException ce) {
-            assertEquals("internal context update failed on context album \"Album:0.0.1\" "
-                            + "in model \"PolicyModel:0.0.1\", "
-                            + "schema \"Schema:0.0.1\" on existing context model does not equal "
-                            + "schema \"IncompatibleSchema:0.0.1\" on incoming model", ce.getMessage());
-        }
+        assertThatThrownBy(() -> context.update(incompatiblePolicyModel, false)).hasMessage(
+            "internal context update failed on context album \"Album:0.0.1\" " + "in model \"PolicyModel:0.0.1\", "
+                + "schema \"Schema:0.0.1\" on existing context model does not equal "
+                + "schema \"IncompatibleSchema:0.0.1\" on incoming model");
 
         assertEquals(policyModel.getKey().getId(), context.getKey().getId());
 
-        context.update(newVersionPolicyModel);
+        context.update(newVersionPolicyModel, false);
         assertEquals(newVersionPolicyModel.getKey().getId(), context.getKey().getId());
 
-        context.update(newPolicyModel);
+        context.update(newPolicyModel, true);
         assertEquals(newPolicyModel.getKey().getId(), context.getKey().getId());
     }
 }
diff --git a/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImplTest.java b/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImplTest.java
index 6d35adc54..2663dfc0d 100644
--- a/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImplTest.java
+++ b/core/core-engine/src/test/java/org/onap/policy/apex/core/engine/engine/impl/ApexEngineImplTest.java
@@ -1,25 +1,27 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2018 Ericsson. All rights reserved.
+ *  Modifications 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.
- * 
+ *
  * SPDX-License-Identifier: Apache-2.0
  * ============LICENSE_END=========================================================
  */
 
 package org.onap.policy.apex.core.engine.engine.impl;
 
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -30,7 +32,6 @@ import static org.junit.Assert.fail;
 import java.io.IOException;
 import java.lang.reflect.Field;
 import java.util.HashMap;
-
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
@@ -50,7 +51,6 @@ import org.onap.policy.apex.core.engine.event.EnEvent;
 import org.onap.policy.apex.core.engine.executor.StateMachineExecutor;
 import org.onap.policy.apex.core.engine.executor.exception.StateMachineException;
 import org.onap.policy.apex.model.basicmodel.concepts.ApexException;
-import org.onap.policy.apex.model.basicmodel.concepts.ApexRuntimeException;
 import org.onap.policy.apex.model.basicmodel.concepts.AxArtifactKey;
 import org.onap.policy.apex.model.basicmodel.concepts.AxReferenceKey;
 import org.onap.policy.apex.model.basicmodel.service.ModelService;
@@ -167,161 +167,79 @@ public class ApexEngineImplTest {
     }
 
     @Test
-    public void testSanity() {
+    public void testSanity() throws ApexException {
         AxArtifactKey engineKey = new AxArtifactKey("Engine:0.0.1");
         ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
         assertNotNull(engine);
         assertEquals(engineKey, engine.getKey());
 
-        try {
-            engine.start();
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("start()<-Engine:0.0.1,STOPPED,  cannot start engine, "
-                            + "engine has not been initialized, its model is not loaded", ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.start()).hasMessage("start()<-Engine:0.0.1,STOPPED,  cannot start engine, "
+                            + "engine has not been initialized, its model is not loaded");
 
-        try {
-            engine.stop();
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("stop()<-Engine:0.0.1,STOPPED, cannot stop engine, " + "engine is already stopped",
-                            ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.stop())
+            .hasMessage("stop()<-Engine:0.0.1,STOPPED, cannot stop engine, " + "engine is already stopped");
 
         assertEquals(AxEngineState.STOPPED, engine.getState());
         assertEquals(0, engine.getEngineContext().size());
         assertEquals(engineKey, engine.getEngineStatus().getKey());
         assertNull(engine.getInternalContext());
 
-        try {
-            engine.clear();
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.clear();
 
-        try {
-            engine.addEventListener(null, null);
-            fail("test should throw an exception");
-        } catch (ApexRuntimeException ae) {
-            assertEquals("addEventListener()<-Engine:0.0.1,STOPPED, listenerName is null", ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.addEventListener(null, null))
+            .hasMessage("addEventListener()<-Engine:0.0.1,STOPPED, listenerName is null");
 
-        try {
-            engine.addEventListener("myListener", null);
-            fail("test should throw an exception");
-        } catch (ApexRuntimeException ae) {
-            assertEquals("addEventListener()<-Engine:0.0.1,STOPPED, listener is null", ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.addEventListener("myListener", null))
+            .hasMessage("addEventListener()<-Engine:0.0.1,STOPPED, listener is null");
 
-        try {
-            engine.removeEventListener(null);
-            fail("test should throw an exception");
-        } catch (ApexRuntimeException ae) {
-            assertEquals("removeEventListener()<-Engine:0.0.1,STOPPED, listenerName is null", ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.removeEventListener(null))
+            .hasMessage("removeEventListener()<-Engine:0.0.1,STOPPED, listenerName is null");
 
-        try {
-            engine.addEventListener("myListener", new DummyListener());
-            engine.removeEventListener("myListener");
-        } catch (Exception e) {
-            fail("test should not throw an exception");
-        }
+        engine.addEventListener("myListener", new DummyListener());
+        engine.removeEventListener("myListener");
 
         assertNull(engine.createEvent(null));
 
         assertFalse(engine.handleEvent(null));
 
-        try {
-            engine.updateModel(null);
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("updateModel()<-Engine:0.0.1, Apex model is not defined, it has a null value",
-                            ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.updateModel(null, false))
+            .hasMessage("updateModel()<-Engine:0.0.1, Apex model is not defined, it has a null value");
 
-        try {
-            engine.updateModel(policyModel);
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.updateModel(policyModel, false);
 
         // Force a context exception
         ModelService.registerModel(AxPolicyModel.class, new AxPolicyModel());
-        try {
-            engine.updateModel(incompatiblePolicyModel);
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("updateModel()<-Engine:0.0.1, error setting the context for engine \"Engine:0.0.1\"",
-                            ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.updateModel(incompatiblePolicyModel, false))
+            .hasMessage("updateModel()<-Engine:0.0.1, error setting the context for engine \"Engine:0.0.1\"");
 
-        try {
-            engine.updateModel(policyModel);
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.updateModel(policyModel, false);
 
         assertNotNull(engine.getInternalContext());
         assertEquals(1, engine.getEngineContext().size());
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
-        try {
-            engine.start();
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("start()<-Engine:0.0.1,READY, cannot start engine, engine not in state STOPPED",
-                            ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.start())
+            .hasMessage("start()<-Engine:0.0.1,READY, cannot start engine, engine not in state STOPPED");
 
-        try {
-            engine.clear();
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("clear()<-Engine:0.0.1,READY, cannot clear engine, engine is not stopped", ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.clear())
+            .hasMessage("clear()<-Engine:0.0.1,READY, cannot clear engine, engine is not stopped");
 
-        try {
-            engine.stop();
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.clear();
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.clear();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.start();
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("start()<-Engine:0.0.1,STOPPED,  cannot start engine, "
-                            + "engine has not been initialized, its model is not loaded", ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.start()).hasMessage("start()<-Engine:0.0.1,STOPPED,  cannot start engine, "
+            + "engine has not been initialized, its model is not loaded");
 
-        try {
-            engine.updateModel(policyModel);
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.updateModel(policyModel, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
         assertNull(engine.createEvent(null));
 
@@ -332,101 +250,52 @@ public class ApexEngineImplTest {
         assertTrue(engine.handleEvent(event));
         assertEquals(AxEngineState.READY, engine.getState());
 
-        try {
-            engine.stop();
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.addEventListener("myListener", new DummyListener());
-        } catch (Exception e) {
-            fail("test should not throw an exception");
-        }
+        engine.addEventListener("myListener", new DummyListener());
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
-        try {
-            engine.updateModel(policyModel);
-            fail("test should throw an exception");
-        } catch (ApexException ae) {
-            assertEquals("updateModel()<-Engine:0.0.1, cannot update model, "
-                            + "engine should be stopped but is in state READY", ae.getMessage());
-        }
+        assertThatThrownBy(() -> engine.updateModel(policyModel, false)).hasMessage(
+            "updateModel()<-Engine:0.0.1, cannot update model, engine should be stopped but is in state READY");
 
         assertTrue(engine.handleEvent(event));
         assertEquals(AxEngineState.READY, engine.getState());
 
-        try {
-            engine.stop();
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.addEventListener("badListener", new DummyEnEventListener());
-        } catch (Exception e) {
-            fail("test should not throw an exception");
-        }
+        engine.addEventListener("badListener", new DummyEnEventListener());
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
         assertFalse(engine.handleEvent(event));
         assertEquals(AxEngineState.READY, engine.getState());
-        try {
-            engine.stop();
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.stop();
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.removeEventListener("badListener");
-            engine.addEventListener("slowListener", new DummySlowEnEventListener());
-        } catch (Exception e) {
-            fail("test should not throw an exception");
-        }
+        engine.removeEventListener("badListener");
+        engine.addEventListener("slowListener", new DummySlowEnEventListener());
     }
 
     @Test
-    public void testState() throws InterruptedException {
+    public void testState() throws InterruptedException, ApexException {
         AxArtifactKey engineKey = new AxArtifactKey("Engine:0.0.1");
         ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
         assertNotNull(engine);
         assertEquals(engineKey, engine.getKey());
 
-        try {
-            engine.updateModel(policyModel);
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.updateModel(policyModel, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
         DummySlowEnEventListener slowListener = new DummySlowEnEventListener();
-        try {
-            engine.addEventListener("slowListener", slowListener);
-        } catch (Exception e) {
-            fail("test should not throw an exception");
-        }
+        engine.addEventListener("slowListener", slowListener);
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
         assertEquals(AxEngineState.READY, engine.getState());
 
@@ -437,6 +306,7 @@ public class ApexEngineImplTest {
         // 1 second is less than the 3 second wait on engine stopping
         slowListener.setWaitTime(1000);
         (new Thread() {
+            @Override
             public void run() {
                 assertTrue(engine.handleEvent(event));
                 assertEquals(AxEngineState.STOPPED, engine.getState());
@@ -466,6 +336,7 @@ public class ApexEngineImplTest {
         // 4 seconds is more than the 3 second wait on engine stopping
         slowListener.setWaitTime(4000);
         (new Thread() {
+            @Override
             public void run() {
                 assertTrue(engine.handleEvent(event));
                 assertEquals(AxEngineState.STOPPED, engine.getState());
@@ -492,30 +363,22 @@ public class ApexEngineImplTest {
 
     @Test
     public void testStateMachineError() throws InterruptedException, IllegalArgumentException, IllegalAccessException,
-                    NoSuchFieldException, SecurityException {
+                    NoSuchFieldException, SecurityException, ApexException {
 
         AxArtifactKey engineKey = new AxArtifactKey("Engine:0.0.1");
         ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
         assertNotNull(engine);
         assertEquals(engineKey, engine.getKey());
 
-        try {
-            engine.updateModel(policyModel);
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.updateModel(policyModel, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
         final Field smHandlerField = engine.getClass().getDeclaredField("stateMachineHandler");
         smHandlerField.setAccessible(true);
         smHandlerField.set(engine, smHandlerMock);
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
         assertEquals(AxEngineState.READY, engine.getState());
 
@@ -556,45 +419,29 @@ public class ApexEngineImplTest {
 
     @Test
     public void testStateMachineHandler() throws InterruptedException, IllegalArgumentException, IllegalAccessException,
-                    NoSuchFieldException, SecurityException {
+                    NoSuchFieldException, SecurityException, ApexException {
         AxArtifactKey engineKey = new AxArtifactKey("Engine:0.0.1");
         ApexEngineImpl engine = (ApexEngineImpl) new ApexEngineFactory().createApexEngine(engineKey);
         assertNotNull(engine);
         assertEquals(engineKey, engine.getKey());
 
-        try {
-            engine.updateModel(policyModelWithStates);
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.updateModel(policyModelWithStates, false);
+        assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
         AxArtifactKey eventKey = new AxArtifactKey("Event:0.0.1");
         EnEvent event = engine.createEvent(eventKey);
         assertEquals(eventKey, event.getKey());
 
-        try {
-            engine.stop();
-            assertEquals(AxEngineState.STOPPED, engine.getState());
-        } catch (ApexException ae) {
-            fail("test should not throw an exception");
-        }
-        
+        engine.stop();
         assertEquals(AxEngineState.STOPPED, engine.getState());
 
-        try {
-            engine.start();
-            assertEquals(AxEngineState.READY, engine.getState());
-        } catch (ApexException e) {
-            fail("test should not throw an exception");
-        }
+        assertEquals(AxEngineState.STOPPED, engine.getState());
+
+        engine.start();
+        assertEquals(AxEngineState.READY, engine.getState());
 
         assertEquals(AxEngineState.READY, engine.getState());