PauseableThread.java

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.utils;

/**
 * A pausable thread. The runnable must not execute an inifite loop but should return control to the thread as often as
 * possible so that the thread can actually pause.
 * 
 * @author mzechner
 */
public class PauseableThread extends Thread {
	final Runnable runnable;
	boolean paused = false;
	boolean exit = false;

	/**
	 * Constructs a new thread setting the runnable which will be called repeatadly in a loop.
	 * 
	 * @param runnable
	 *            the runnable.
	 */
	public PauseableThread(Runnable runnable) {
		this.runnable = runnable;
	}

	public void run() {
		while (true) {
			synchronized (this) {
				try {
					while (paused)
						wait();
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}

			if (exit)
				return;

			runnable.run();
		}
	}

	/** Pauses the thread. This call is non-blocking */
	public void onPause() {
		paused = true;
	}

	/** Resumes the thread. This call is non-blocking */
	public void onResume() {
		synchronized (this) {
			paused = false;
			this.notifyAll();
		}
	}

	/** @return whether this thread is paused or not */
	public boolean isPaused() {
		return paused;
	}

	/** Stops this thread */
	public void stopThread() {
		exit = true;
		if (paused)
			onResume();
	}
}