[Bug292967] Second part of request coalescing + unit tests + minor fixes.

[deliverable/tracecompass.git] / org.eclipse.linuxtools.tmf / src / org / eclipse / linuxtools / tmf / request / TmfRequestExecutor.java

/*******************************************************************************
 * Copyright (c) 2009, 2010 Ericsson
 * 
 * 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:
 *   Francois Chouinard - Initial API and implementation
 *******************************************************************************/

package org.eclipse.linuxtools.tmf.request;

import java.util.Queue;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;

/**
 * <b><u>TmfRequestExecutor</u></b>
 *
 * Implement me. Please.
 */
public class TmfRequestExecutor implements Executor {

	private final Executor fExecutor;
	private final Queue<Runnable> fRequests = new LinkedBlockingQueue<Runnable>();
	private Runnable fRequest;
	
	public TmfRequestExecutor(Executor executor) {
		fExecutor = executor;
	}

	public TmfRequestExecutor() {
		this(Executors.newSingleThreadExecutor());
	}

	public void execute(final Runnable request) {
		fRequests.offer(new Runnable() {
			public void run() {
				try {
					request.run();
				} finally {
					scheduleNext();
				}
			}
		});
		if (fRequest == null) {
			scheduleNext();
		}
	}

	protected synchronized void scheduleNext() {
		if ((fRequest = fRequests.poll()) != null) {
			fExecutor.execute(fRequest);
		}
	}

	public synchronized void queueRequest(Runnable request) {
		fRequests.add(request);
		scheduleNext();
	}

}