/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
/*
 *
 * @author Toni Kalajainen
 */
package org.simantics.utils.threads;

import java.util.concurrent.Executor;

import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Widget;

public class SWTThread implements IThreadWorkQueue, Executor {

	final Display display;
	
	public static IThreadWorkQueue getThreadAccess(Display display)
	{
		return new SWTThread(display);
	}
	
	public static IThreadWorkQueue getThreadAccess(Widget widget)
	{
		return new SWTThread(widget.getDisplay());
	}
	
	public static IThreadWorkQueue getThreadAccess() {
		return new SWTThread(Display.getDefault());
	}
	
	SWTThread(Display display)
	{
		this.display = display;
	}
	
	@Override
	public Thread asyncExec(Runnable runnable) {
		// Don't accept work if the SWT thread is disposed.
		if (display.isDisposed())
			return null;
		display.asyncExec(runnable);
		return display.getThread();
	}

	@Override
	public boolean syncExec(Runnable runnable) {
		// Don't accept work if the SWT thread is disposed.
		if (display.isDisposed())
			return false;
		if (display.getThread() == Thread.currentThread ())
			runnable.run();
		else 
			display.syncExec(runnable);
		return true;
	}

	@Override
	public boolean currentThreadAccess() {
		// A disposed SWT thread can never be the current thread access
		if (display.isDisposed())
			return false;
		return display.getThread() == Thread.currentThread ();
	}

	@Override
	public Thread getThread() {
		// Use null to indicate disposed SWT thread.
		if (display.isDisposed())
			return null;
		return display.getThread();
	}
	
	@Override
	public String toString() {
		return "SWT Thread";
	}

	@Override
	public void execute(Runnable command) {
		syncExec(command);
	}
}