CM-690 trait extension

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@117473 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/traitextender/ExtenderImpl.java

@@ -0,0 +1,105 @@
+/* 
+ * Copyright (C) 2005-2015 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see http://www.gnu.org/licenses/.
+ */
+
+package org.alfresco.traitextender;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+public class ExtenderImpl extends Extender
+{
+    private static Log logger = LogFactory.getLog(Extender.class);
+
+  
+
+    private List<ExtensionBundle> bundles = new LinkedList<ExtensionBundle>();
+
+    private Map<ExtensionPoint<?, ?>, ExtensionFactory<?>> pointFactories = new ConcurrentHashMap<ExtensionPoint<?, ?>, ExtensionFactory<?>>();
+
+    public synchronized void start(ExtensionBundle bundle)
+    {
+        bundles.add(bundle);
+        bundle.start(this);
+    }
+
+    public void stop(ExtensionBundle bundle)
+    {
+        bundle.stop(this);
+        bundles.remove(bundle);
+    }
+
+    public synchronized void stopAll()
+    {
+        List<ExtensionBundle> bundlesCopy = new LinkedList<>(bundles);
+        for (ExtensionBundle bundle : bundlesCopy)
+        {
+            stop(bundle);
+        }
+    }
+
+    public synchronized <E, M extends Trait> E getExtension(Extensible anExtensible, ExtensionPoint<E, M> point)
+    {
+        E extension = null;
+
+        //consistency is checked at registration time 
+        @SuppressWarnings("unchecked")
+        ExtensionFactory<E> factory = (ExtensionFactory<E>) pointFactories.get(point);
+
+        if (factory != null)
+        {
+            ExtendedTrait<M> exTrait = anExtensible.getTrait(point.getTraitAPI());
+
+            extension = exTrait.getExtension(point.getExtensionAPI());
+
+            if (extension == null)
+            {
+                extension = exTrait.extend(point.getExtensionAPI(),
+                                           factory);
+                if (logger.isDebugEnabled())
+                {
+                    logger.debug("trait extension leak trace : " + System.identityHashCode(extension) + " : "
+                                + System.identityHashCode(exTrait) + " : " + System.identityHashCode(extension));
+                }
+            }
+        }
+        return extension;
+    }
+
+    public synchronized void register(ExtensionPoint<?, ?> point, ExtensionFactory<?> factory)
+    {
+        // point->factory type consistency checks
+        if (!factory.canCreateExtensionFor(point))
+        {
+            throw new InvalidExtension("Invalid extension factory registry entry : " + point + "->" + factory);
+        }
+        pointFactories.put(point,
+                           factory);
+    }
+
+    public synchronized void unregister(ExtensionPoint<?, ?> point)
+    {
+        pointFactories.remove(point);
+    }
+
+}