Add a LifeCycleListener interface so that extension points or extension can be called back upon the start/stop of the extension point registry

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@785699 13f79535-47bb-0310-9956-ffa450edef68

7 files changed, 140 insertions, 30 deletions

diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java
index 3ea587c5f2..7fe79d6c00 100644
--- a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java
@@ -65,8 +65,8 @@ public class DefaultExtensionPointRegistry implements ExtensionPointRegistry {
         if (extensionPoint == null) {
             throw new IllegalArgumentException("Cannot register null as an ExtensionPoint");
         }
-        if (extensionPoint instanceof ModuleActivator) {
-            ((ModuleActivator)extensionPoint).start(this);
+        if (extensionPoint instanceof LifeCycleListener) {
+            ((LifeCycleListener)extensionPoint).start();
         }
         Set<Class<?>> interfaces = getAllInterfaces(extensionPoint.getClass());
         for (Class<?> i : interfaces) {
@@ -170,8 +170,8 @@ public class DefaultExtensionPointRegistry implements ExtensionPointRegistry {
             throw new IllegalArgumentException("Cannot remove null as an ExtensionPoint");
         }
 
-        if (extensionPoint instanceof ModuleActivator) {
-            ((ModuleActivator)extensionPoint).stop(this);
+        if (extensionPoint instanceof LifeCycleListener) {
+            ((LifeCycleListener)extensionPoint).stop();
         }
 
         Set<Class<?>> interfaces = getAllInterfaces(extensionPoint.getClass());
@@ -208,17 +208,21 @@ public class DefaultExtensionPointRegistry implements ExtensionPointRegistry {
         }
     }
 
-    public void destroy() {
+    public void start() {
+        // Do nothing
+    }
+
+    public void stop() {
         // Get a unique map as an extension point may exist in the map by different keys
-        Map<ModuleActivator, ModuleActivator> map = new IdentityHashMap<ModuleActivator, ModuleActivator>();
+        Map<LifeCycleListener, LifeCycleListener> map = new IdentityHashMap<LifeCycleListener, LifeCycleListener>();
         for (Object extp : extensionPoints.values()) {
-            if (extp instanceof ModuleActivator) {
-                ModuleActivator activator = (ModuleActivator)extp;
-                map.put(activator, activator);
+            if (extp instanceof LifeCycleListener) {
+                LifeCycleListener listener = (LifeCycleListener)extp;
+                map.put(listener, listener);
             }
         }
-        for (ModuleActivator activator : map.values()) {
-            activator.stop(this);
+        for (LifeCycleListener listener : map.values()) {
+            listener.stop();
         }
         extensionPoints.clear();
     }
diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultModuleActivatorExtensionPoint.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultModuleActivatorExtensionPoint.java
index f9228efd71..60d933a443 100644
--- a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultModuleActivatorExtensionPoint.java
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultModuleActivatorExtensionPoint.java
@@ -40,11 +40,14 @@ public class DefaultModuleActivatorExtensionPoint implements ModuleActivatorExte
     private final static Logger logger = Logger.getLogger(DefaultModuleActivatorExtensionPoint.class.getName());
     private List<ModuleActivator> activators = new ArrayList<ModuleActivator>();
     private boolean loadedActivators;
+    private boolean started;
+    private ExtensionPointRegistry registry;
 
     /**
      * Constructs a new extension point.
      */
-    public DefaultModuleActivatorExtensionPoint() {
+    public DefaultModuleActivatorExtensionPoint(ExtensionPointRegistry registry) {
+        this.registry = registry;
     }
 
     public void addModuleActivator(ModuleActivator activator) {
@@ -56,8 +59,10 @@ public class DefaultModuleActivatorExtensionPoint implements ModuleActivatorExte
         return activators;
     }
 
-    public void removeModuleActivator(Object activator) {
-        activators.remove(activator);
+    public void removeModuleActivator(ModuleActivator activator) {
+        if (activators.remove(activator)) {
+            activator.stop(registry);
+        }
     }
 
     /**
@@ -109,4 +114,35 @@ public class DefaultModuleActivatorExtensionPoint implements ModuleActivatorExte
         loadedActivators = true;
     }
 
+    public void start() {
+        if (started) {
+            return;
+        }
+        getModuleActivators();
+        for (ModuleActivator activator : activators) {
+            try {
+                activator.start(registry);
+            } catch (Throwable e) {
+                // Ignore the failing module for now
+                logger.log(Level.SEVERE, e.getMessage(), e);
+            }
+        }
+        started = true;
+    }
+
+    public void stop() {
+        if (!started) {
+            return;
+        }
+        for (int i = activators.size() - 1; i >= 0; i--) {
+            try {
+                activators.get(i).stop(registry);
+            } catch (Throwable e) {
+                // Ignore the failing module for now
+                logger.log(Level.SEVERE, e.getMessage(), e);
+            }
+        }
+        started = false;
+    }
+
 }
diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java
index c7ff4e1858..1004fc3019 100644
--- a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java
@@ -23,7 +23,10 @@ import java.io.IOException;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Modifier;
+import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.IdentityHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -40,6 +43,7 @@ public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint {
     private Map<Class<?>, Object> utilities = new ConcurrentHashMap<Class<?>, Object>();
 
     private ExtensionPointRegistry extensionPoints;
+    private List<Object> unmapped = new ArrayList<Object>();
 
     /**
      * Constructs a new extension point.
@@ -61,6 +65,9 @@ public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint {
             throw new IllegalArgumentException("Cannot register null as a Service");
         }
 
+        if(utility instanceof LifeCycleListener) {
+            ((LifeCycleListener) utility).start();
+        }
         Set<Class<?>> interfaces = getAllInterfaces(utility.getClass());
         for (Class<?> i : interfaces) {
             utilities.put(i, utility);
@@ -110,6 +117,10 @@ public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint {
             throw new IllegalArgumentException("Cannot remove null as a Service");
         }
 
+        if(utility instanceof LifeCycleListener) {
+            ((LifeCycleListener) utility).stop();
+        }
+
         Set<Class<?>> interfaces = getAllInterfaces(utility.getClass());
         for (Class<?> i : interfaces) {
             utilities.remove(i);
@@ -178,6 +189,9 @@ public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint {
                     }
                     // Cache the loaded utility
                     addUtility(utility);
+                    if (newInstance) {
+                        unmapped.add(utility);
+                    }
                 }
             } catch (InvocationTargetException e) {
                 throw new IllegalArgumentException(e);
@@ -194,4 +208,29 @@ public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint {
         return utilityType.cast(utility);
     }
 
+    public void start() {
+        // NOOP
+    }
+
+    public void stop() {
+        // Get a unique map as an extension point may exist in the map by different keys
+        Map<LifeCycleListener, LifeCycleListener> map = new IdentityHashMap<LifeCycleListener, LifeCycleListener>();
+        for (Object util : utilities.values()) {
+            if (util instanceof LifeCycleListener) {
+                LifeCycleListener listener = (LifeCycleListener)util;
+                map.put(listener, listener);
+            }
+        }
+        for (Object util : unmapped) {
+            if (util instanceof LifeCycleListener) {
+                LifeCycleListener listener = (LifeCycleListener)util;
+                map.put(listener, listener);
+            }
+        }
+        for (LifeCycleListener listener : map.values()) {
+            listener.stop();
+        }
+        utilities.clear();
+    }
+
 }
diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ExtensionPointRegistry.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ExtensionPointRegistry.java
index d5647d6601..4c6fbd283f 100644
--- a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ExtensionPointRegistry.java
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ExtensionPointRegistry.java
@@ -27,7 +27,7 @@ package org.apache.tuscany.sca.core;
  *
  * @version $Rev$ $Date$
  */
-public interface ExtensionPointRegistry {
+public interface ExtensionPointRegistry extends LifeCycleListener {
 
     /**
      * Add an extension point to the registry
@@ -53,9 +53,4 @@ public interface ExtensionPointRegistry {
      * @throws IllegalArgumentException if extensionPoint is null
      */
     void removeExtensionPoint(Object extensionPoint);
-
-    /**
-     * Destroy the extension point registry
-     */
-    void destroy();
 }
diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/LifeCycleListener.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/LifeCycleListener.java
new file mode 100644
index 0000000000..ff0ab113b2
--- /dev/null
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/LifeCycleListener.java
@@ -0,0 +1,36 @@
+/*

+ * Licensed to the Apache Software Foundation (ASF) under one

+ * or more contributor license agreements.  See the NOTICE file

+ * distributed with this work for additional information

+ * regarding copyright ownership.  The ASF licenses this file

+ * to you 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.

+ */

+

+package org.apache.tuscany.sca.core;

+

+/**

+ * A listener that responds to the start/stop event of the ExtensionPointRegistry. Tuscany extension

+ * points or extensions can implement this interface to receive callbacks when the registry is started

+ * or stopped

+ */

+public interface LifeCycleListener {

+    /**

+     * The method will be invoked when the extension point registry is started

+     */

+    void start();

+    /**

+     * The method will be invoked when the extension point registry is stopped

+     */

+    void stop();

+}

diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ModuleActivatorExtensionPoint.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ModuleActivatorExtensionPoint.java
index ec0f12b8ba..7070d33f2c 100644
--- a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ModuleActivatorExtensionPoint.java
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/ModuleActivatorExtensionPoint.java
@@ -6,15 +6,15 @@
  * to you 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.    
+ * under the License.
  */
 
 package org.apache.tuscany.sca.core;
@@ -27,7 +27,7 @@ import java.util.List;
  *
  * @version $Rev$ $Date$
  */
-public interface ModuleActivatorExtensionPoint {
+public interface ModuleActivatorExtensionPoint extends LifeCycleListener {
 
     /**
      * Add a module activator extension to the extension point
@@ -49,5 +49,5 @@ public interface ModuleActivatorExtensionPoint {
      *
      * @throws IllegalArgumentException if activator is null
      */
-    void removeModuleActivator(Object activator);
+    void removeModuleActivator(ModuleActivator activator);
 }
diff --git a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/UtilityExtensionPoint.java b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/UtilityExtensionPoint.java
index 9804234850..4cf1db16d1 100644
--- a/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/UtilityExtensionPoint.java
+++ b/java/sca/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/UtilityExtensionPoint.java
@@ -6,15 +6,15 @@
  * to you 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.    
+ * under the License.
  */
 
 package org.apache.tuscany.sca.core;
@@ -25,7 +25,7 @@ package org.apache.tuscany.sca.core;
  *
  * @version $Rev$ $Date$
  */
-public interface UtilityExtensionPoint {
+public interface UtilityExtensionPoint extends LifeCycleListener {
 
     /**
      * Add a utility to the extension point
@@ -53,7 +53,7 @@ public interface UtilityExtensionPoint {
      * @throws IllegalArgumentException if utilityType is null
      */
     <T> T getUtility(Class<T> utilityType, boolean newInstance);
-    
+
     /**
      * Remove a utility
      * @param utility The utility to remove