timertask.java

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/*
 * Java core library component.
 *
 * Copyright (c) 1999
 *	Archie L. Cobbs.  All rights reserved.
 * Copyright (c) 1999
 *	Transvirtual Technologies, Inc.  All rights reserved.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file.
 *
 * Author: Archie L. Cobbs <[e-mail]>
 */

package java.util;

public abstract class TimerTask implements Runnable {
	Timer timer;			// non-null IFF currently scheduled
	boolean fixedRate;		// fixed-rate or fixed-delay
	boolean changed;		// true if run() changes timer or task
	long period;			// repeat period (or -1 for none)
	long time;			// time of next expiration
	private long lastTime;		// time of last expiration

	public TimerTask() {
	}

	public abstract void run();

	public boolean cancel() {
		try {
			return timer.unschedule(this);
		} catch (NullPointerException e) {
			return false;
		}
	}

	// These two routines must be synchronized because of the long value
	public synchronized long scheduledExecutionTime() {
		return lastTime;
	}

	synchronized void setScheduledExecutionTime(long when) {
		lastTime = when;
	}
}