EventTarget.java

/**
 * Copyright (c) 2005-2006 Aptana, Inc.
 *
 * 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. If redistributing this code,
 * this entire header must remain intact.
 */
package org.eclipse.eclipsemonkey.lang.javascript.events;


import java.util.ArrayList;
import java.util.Hashtable;

import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.PlatformUI;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.ScriptableObject;

/**
 * @author Kevin Lindsey
 */
public abstract class EventTarget extends ScriptableObject implements IEventTarget
{
	/*
	 * Fields
	 */
	private Hashtable _events;

	/*
	 * Constructors
	 */

	/**
	 * Create a new instance of EventTarget
	 */
	public EventTarget()
	{
		String[] names = new String[] { "addEventListener", "removeEventListener" }; //$NON-NLS-1$ //$NON-NLS-2$

		this.defineFunctionProperties(names, EventTarget.class, READONLY | PERMANENT);
	}

	/*
	 * Methods
	 */

	/**
	 * @param event 
	 */
	public void fireEventListeners(Event event)
	{
		this.fireEventListeners(event.getType(), new Object[] { event });
	}

	/**
	 * @param eventType 
	 * @param args 
	 */
	public void fireEventListeners(String eventType, Object[] args)
	{
		if (this._events != null && this._events.containsKey(eventType))
		{
			ArrayList handlers = (ArrayList) _events.get(eventType);

			for (int i = 0; i < handlers.size(); i++)
			{
				Object eventHandler = handlers.get(i);

				if (eventHandler instanceof Function)
				{
					final Object[] fArgs = args;
					final Function f = (Function) eventHandler;
					final Scriptable scope = f.getParentScope();
					
					final IWorkbench workbench = PlatformUI.getWorkbench();
					Display display = workbench.getDisplay();
					
					// execute callback in the correct thread
					display.syncExec(new Runnable()
					{
						public void run() {
							Context cx = Context.enter();
							
							try
							{
								f.call(cx, scope, scope, fArgs);
							}	
							finally
							{
								Context.exit();
							}
						}
						
					});
				}
			}
		}

	}

	/**
	 * @param eventType 
	 * @param eventHandler 
	 */
	public void addEventListener(String eventType, Object eventHandler)
	{
		if (this._events == null)
		{
			this._events = new Hashtable();
		}

		if (this._events.containsKey(eventType) == false)
		{
			this._events.put(eventType, new ArrayList());
		}

		ArrayList handlers = (ArrayList) this._events.get(eventType);

		handlers.add(eventHandler);
	}

	/**
	 * @param eventType 
	 * @param eventHandler 
	 */
	public void removeEventListener(String eventType, Object eventHandler)
	{
		if (this._events != null)
		{
			if (this._events.containsKey(eventType))
			{
				ArrayList handlers = (ArrayList) this._events.get(eventType);

				handlers.remove(eventHandler);
			}
		}
	}
}