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/*
 * Copyright (C) 2008 Alexander Christian . All rights reserved.
 *
 * This file is part of SIMON.
 *
 *   SIMON 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 3 of the License, or
 *   (at your option) any later version.
 *
 *   SIMON 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with SIMON.  If not, see .
 */
package host.anzo.simon;

import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

/**
 * A simple monitor class whose instance can have a sequence id.
 *
 * @author achr
 */
public class Monitor {
	private final Semaphore s = new Semaphore(1);

	/**
	 * Creates a monitor object
	 */
	protected Monitor() {
		try {
			s.acquire();
		} catch (InterruptedException ex) {
		}
	}

	/**
	 * Waits for a signal. if it becomes available within the given waiting
	 * time, true will be returned. Otherwise you will get false
	 *
	 * @param timeout timeout for signal to receive
	 * @return true, if signal received, false if not
	 */
	public boolean waitForSignal(long timeout) {
		try {
			return s.tryAcquire(timeout, TimeUnit.MILLISECONDS);
		} catch (InterruptedException ex) {
			return false;
		}
	}

	/**
	 * Provide the signal
	 */
	public void signal() {
		s.release();
	}

	public void reset() {
		if (s.availablePermits() == 1) {
			s.acquireUninterruptibly();
		}
	}
}