1 files changed, 154 insertions, 0 deletions
diff --git a/sca-java-2.x/tags/2.0.1-RC1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultModuleActivatorExtensionPoint.java b/sca-java-2.x/tags/2.0.1-RC1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultModuleActivatorExtensionPoint.java
new file mode 100644
index 0000000000..99792d0215
--- /dev/null
+++ b/sca-java-2.x/tags/2.0.1-RC1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultModuleActivatorExtensionPoint.java
@@ -0,0 +1,154 @@
+/*
+ * 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;
+
+import static org.apache.tuscany.sca.extensibility.ServiceHelper.newInstance;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.apache.tuscany.sca.extensibility.ServiceDeclaration;
+
+/**
+ * Default implementation of an extension point to hold Tuscany module activators.
+ *
+ * @version $Rev$ $Date$
+ */
+public class DefaultModuleActivatorExtensionPoint implements ModuleActivatorExtensionPoint {
+    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(ExtensionPointRegistry registry) {
+        this.registry = registry;
+    }
+
+    public void addModuleActivator(ModuleActivator activator) {
+        activators.add(activator);
+    }
+
+    public List<ModuleActivator> getModuleActivators() {
+        loadModuleActivators();
+        return activators;
+    }
+
+    public void removeModuleActivator(ModuleActivator activator) {
+        if (activators.remove(activator)) {
+            activator.stop();
+        }
+    }
+
+    /**
+     * Dynamically load module activators declared under META-INF/services
+     */
+    private synchronized void loadModuleActivators() {
+        if (loadedActivators)
+            return;
+
+        // Get the activator service declarations
+        Collection<ServiceDeclaration> activatorDeclarations;
+        try {
+            // Load the module activators by ranking
+            activatorDeclarations = registry.getServiceDiscovery().getServiceDeclarations(ModuleActivator.class.getName(), true);
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
+
+        // Load and instantiate module activators
+        for (ServiceDeclaration activatorDeclaration : activatorDeclarations) {
+            if (logger.isLoggable(Level.FINE)) {
+                logger.fine("Loading " + activatorDeclaration.getClassName());
+            }
+            ModuleActivator activator = null;
+            try {
+                Class<ModuleActivator> activatorClass = (Class<ModuleActivator>)activatorDeclaration.loadClass();
+                try {
+                    activator = newInstance(activatorClass, ExtensionPointRegistry.class, registry);
+                } catch (NoSuchMethodException e) {
+                    try {
+                        activator =
+                            newInstance(activatorClass,
+                                        new Class<?>[] {ExtensionPointRegistry.class, Map.class},
+                                        registry,
+                                        activatorDeclaration.getAttributes());
+
+                    } catch (NoSuchMethodException e1) {
+                        activator = newInstance(activatorClass);
+
+                    }
+                }
+            } catch (Throwable e) {
+                String optional = activatorDeclaration.getAttributes().get("optional");
+                if ("true".equalsIgnoreCase(optional)) {
+                    // If the optional flag is true, just log the error
+                    logger.log(Level.SEVERE, e.getMessage(), e);
+                    continue;
+                } else {
+                    throw new IllegalArgumentException(e);
+                }
+            }
+            addModuleActivator(activator);
+        }
+
+        loadedActivators = true;
+    }
+
+    public void start() {
+        if (started) {
+            return;
+        }
+        getModuleActivators();
+        for (ModuleActivator activator : activators) {
+            try {
+                activator.start();
+            } 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();
+            } catch (Throwable e) {
+                // Ignore the failing module for now
+                logger.log(Level.SEVERE, e.getMessage(), e);
+            }
+        }
+        started = false;
+    }
+
+}