RemoteAgent.java

/**
 * Copyright (c) 2006 Ecliptical Software Inc. and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Ecliptical Software Inc. - initial API and implementation
 */
package org.eclipse.ecf.pubsub.model.impl;

import java.io.IOException;
import java.util.Collection;
import java.util.HashSet;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.eclipse.ecf.core.identity.ID;
import org.eclipse.ecf.core.sharedobject.ISharedObjectConfig;
import org.eclipse.ecf.core.sharedobject.ISharedObjectContext;
import org.eclipse.ecf.core.sharedobject.SharedObjectInitException;
import org.eclipse.ecf.example.pubsub.SerializationUtil;
import org.eclipse.ecf.pubsub.ISubscribedService;
import org.eclipse.ecf.pubsub.ISubscriber;
import org.eclipse.ecf.pubsub.impl.SubscribeMessage;
import org.eclipse.ecf.pubsub.impl.UnsubscribeMessage;
import org.eclipse.ecf.pubsub.model.IModelUpdater;
import org.eclipse.ecf.pubsub.model.IReplicaModel;

public class RemoteAgent extends AgentBase implements IReplicaModel, ISubscribedService {
	
	private Collection subscribers;
	
	private final Object subscriptionMutex = new Object();
	
	public void unsubscribe(ID requestorID) {
		synchronized (subscriptionMutex) {
			if (subscribers == null)
				return;
			
			subscribers.remove(requestorID);
			if (subscribers.isEmpty()) {
				ISharedObjectContext ctx = config.getContext();
				try {
					ctx.sendMessage(config.getHomeContainerID(), new UnsubscribeMessage());
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				
				ctx.getSharedObjectManager().removeSharedObject(config.getSharedObjectID());
			}
		}
	}
	
	public void init(ISharedObjectConfig config) throws SharedObjectInitException {
		super.init(config);
		subscribers = new HashSet();
		ID requestorID = (ID) config.getProperties().get(REQUESTOR_ID);
		if (requestorID != null)
			subscribers.add(requestorID);
	}
	
	protected void initializeData(Object data) throws SharedObjectInitException {
		try {
			this.data = SerializationUtil.deserialize((byte[]) data);
		} catch (IOException e) {
			throw new SharedObjectInitException(e);
		} catch (ClassNotFoundException e) {
			throw new SharedObjectInitException(e);
		}
	}
	
	protected void initializeUpdater() throws SharedObjectInitException {
		IExtensionRegistry registry = Platform.getExtensionRegistry();
		if (registry == null)
			throw new SharedObjectInitException("No Platform Extension Registry.");
		
		IConfigurationElement[] elements = registry.getConfigurationElementsFor("org.eclipse.ecf.example.pubsub.modelUpdater");
		for (int i = 0; i < elements.length; ++i) {
			if (updaterID.equals(elements[i].getAttribute("id"))) {
				try {
					updater = (IModelUpdater) elements[i].createExecutableExtension("class");
				} catch (CoreException e) {
					throw new SharedObjectInitException(e);
				} catch (ClassCastException e) {
					throw new SharedObjectInitException(e);
				}

				break;
			}
		}

		if (updater == null)
			throw new SharedObjectInitException("Could not find specified Model Updater.");
	}
	
	protected void activated() {
		ID requestorID = (ID) config.getProperties().get(REQUESTOR_ID);
		if (requestorID != null) {
			Object svc = config.getContext().getSharedObjectManager().getSharedObject(requestorID);
			if (svc instanceof ISubscriber)
				((ISubscriber) svc).subscribed(this);
		}
	}
	
	protected void disconnected() {
		config.getContext().getSharedObjectManager().removeSharedObject(config.getSharedObjectID());
	}
	
	protected void disconnected(ID containerID) {
		if (containerID.equals(config.getHomeContainerID()))
			disconnected();
	}
	
	protected void received(ID containerID, Object data) {
		if (!(data instanceof byte[]))
			return;
		
		if (data instanceof SubscribeMessage) {
			SubscribeMessage msg = (SubscribeMessage) data;
			synchronized (subscriptionMutex) {
				subscribers.add(msg.getRequestorID());
			}
			
			return;
		}
		
		try {
			updater.update(this.data, SerializationUtil.deserialize((byte[]) data));
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}