semaphore.java

Java Communicating Agents是一个用于开发网络反应式信息agent的框架

/*
 * $Source: /home/data/cvsroot/src/jacomma/util/Semaphore.java,v $
 * $Revision: 1.4 $
 * $Date: 2000/10/28 20:09:08 $
 *
 * This file is part of the jacomma framework
 * Copyright (c) 2000 	Dimitrios Vyzovitis
 *			mailto:[e-mail]
 *			
 *
 *			
 *			
 *			
 *
 *	This library is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU Library General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This library is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU Library General Public License for more details.
 *
 *	You should have received a copy of the GNU Library General Public License
 *	along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, 
 *	Boston, MA  02111-1307  USA
 */

package jacomma.util;

/**
 * Simple Semaphore variable (well, not pthread_cond, since this is just synchronization)
 **/
public class Semaphore {
	
	private int count_;

	public Semaphore() {}
	
	public synchronized void post() {
		++count_;
		notifyAll();
	}
	
	public synchronized int get() { return count_; }
	
	public synchronized void sem_wait() throws InterruptedException {
		while( count_ == 0 ) wait();
		--count_;
	}
	
	public synchronized boolean sem_wait( long t ) throws InterruptedException {
		if ( count_ == 0 ) wait( t );
		return (count_ > 0) ? (count_-- > 0) : false;
	}

}