ChordFutureImpl.java

/***************************************************************************
 *                                                                         *
 *                           ChordFutureImpl.java                          *
 *                            -------------------                          *
 *   date                 : 15.10.2005                                     *
 *   copyright            : (C) 2004-2008 Distributed and                  *
 *                              Mobile Systems Group                       *
 *                              Lehrstuhl fuer Praktische Informatik       *
 *                              Universitaet Bamberg                       *
 *                              http://www.uni-bamberg.de/pi/              *
 *   email                : sven.kaffille@uni-bamberg.de                   *
 *   			    		karsten.loesing@uni-bamberg.de                 *
 *                                                                         *
 *                                                                         *
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   A copy of the license can be found in the license.txt file supplied   *
 *   with this software or at: http://www.gnu.org/copyleft/gpl.html        *
 *                                                                         *
 ***************************************************************************/
package de.uniba.wiai.lspi.chord.service.impl;

import de.uniba.wiai.lspi.chord.service.AsynChord;
import de.uniba.wiai.lspi.chord.service.ChordFuture;
import de.uniba.wiai.lspi.chord.service.ServiceException;

/**
 * Abstract implementation of {@link ChordFuture}. Provides common
 * functionality for all {@link ChordFuture} implementations in this package.
 * 
 * @author sven
 * @version 1.0.5
 * 
 */
abstract class ChordFutureImpl implements ChordFuture {

	/**
	 * Indicates that the request to {@link AsynChord} has been completed.
	 */
	private boolean isDone = false;

	/**
	 * Any Exception/Throwable that occured during execution of request
	 * associated with this future.
	 */
	private Throwable throwable = null;

	/**
	 * Instances of this can only be created by sub classes. 
	 * 
	 */
	protected ChordFutureImpl() {
		/*
		 * Nothing to do here. 
		 */
	}

	/**
	 * Indicate that the method associated with this has completed.
	 * 
	 */
	final void setIsDone() {
		synchronized (this) {
			this.isDone = true;
			this.notifyAll();
		}
	}

	/**
	 * Set a {@link Throwable} that occured during execution of method
	 * associated with this.
	 * 
	 * @param t
	 */
	final void setThrowable(Throwable t) {
		this.throwable = t;
	}

	/**
	 * @see ChordFuture
	 */
	public Throwable getThrowable() {
		return this.throwable;
	}

	/**
	 * @see ChordFuture
	 * @return <code>true</code> if operation associated with this has been performed. 
	 * @throws ServiceException
	 */
	public final boolean isDone() throws ServiceException {
		if (this.throwable != null) {
			throw new ServiceException(this.throwable.getMessage(),
					this.throwable);
		}
		return this.isDone;
	}

	/**
	 * @see ChordFuture
	 */
	public void waitForBeingDone() throws ServiceException,
			InterruptedException {
		synchronized (this) {
			while (!this.isDone()) {
				this.wait();
			}
		}
	}

}