Messaging facade for clustered communications to allow implementations from JGroups or Hazelcast to be used.

* PropertyBackedBeanExporter uses the facade, configured with JGroups messaging implementation.
* Unfortunately, some remodelling required before this will work with Ehcache's CacheManagerPeerProviderFactory




git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@33830 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/cluster/HazelcastMessenger.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2005-2012 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.repo.cluster;
+
+import java.io.Serializable;
+
+import org.springframework.extensions.surf.util.ParameterCheck;
+
+import com.hazelcast.core.ITopic;
+import com.hazelcast.core.MessageListener;
+
+/**
+ * Hazelcast-based implementation of the {@link Messenger} interface.
+ * 
+ * @see HazelcastMessengerFactory
+ * @author Matt Ward
+ */
+public class HazelcastMessenger<T extends Serializable> implements Messenger<T>, MessageListener<T>
+{
+    private ITopic<T> topic;
+    private MessageReceiver<T> receiverDelegate;
+    
+    
+    /**
+     * @param topic
+     */
+    public HazelcastMessenger(ITopic<T> topic)
+    {
+        this.topic = topic;
+    }
+
+
+    @Override
+    public void send(T message)
+    {
+        topic.publish(message);
+    }
+
+    @Override
+    public void setReceiver(MessageReceiver<T> receiver)
+    {
+        // Install a delegate to ready to handle incoming messages.
+        receiverDelegate = receiver;
+        // Start receiving messages.
+        topic.addMessageListener(this);
+    }
+
+    @Override
+    public void onMessage(T message)
+    {
+        ParameterCheck.mandatory("message", message);
+        receiverDelegate.onReceive(message);
+    }
+
+    protected String getTopicName()
+    {
+        return topic.getName();
+    }
+
+
+    @Override
+    public boolean isConnected()
+    {
+        return true;
+    }
+}