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Java lang extensions for java6+, a supplement to , replacement of a Guava, commons-lang.
Core utilities, Collection utilities, IO utilities, Cache, Configuration library ...
package com.jn.langx.commandline;
import java.util.Enumeration;
import java.util.Vector;
/**
* Generalization of {@code ExecuteWatchdog}
*
* @see com.jn.langx.commandline.ExecuteWatchdog
*/
public class Watchdog implements Runnable {
private final Vector observers = new Vector(1);
private final long timeout;
private boolean stopped = false;
public Watchdog(final long timeout) {
if (timeout < 1) {
throw new IllegalArgumentException("timeout must not be less than 1.");
}
this.timeout = timeout;
}
public void addTimeoutObserver(final TimeoutObserver to) {
observers.addElement(to);
}
public void removeTimeoutObserver(final TimeoutObserver to) {
observers.removeElement(to);
}
protected final void fireTimeoutOccured() {
final Enumeration e = observers.elements();
while (e.hasMoreElements()) {
e.nextElement().onTimeout(this);
}
}
public synchronized void start() {
stopped = false;
final Thread t = new Thread(this, "WATCHDOG");
t.setDaemon(true);
t.start();
}
public synchronized void stop() {
stopped = true;
notifyAll();
}
public void run() {
final long startTime = System.currentTimeMillis();
boolean isWaiting;
synchronized (this) {
long timeLeft = timeout - (System.currentTimeMillis() - startTime);
isWaiting = timeLeft > 0;
while (!stopped && isWaiting) {
try {
wait(timeLeft);
} catch (final InterruptedException e) {
}
timeLeft = timeout - (System.currentTimeMillis() - startTime);
isWaiting = timeLeft > 0;
}
}
// notify the listeners outside of the synchronized block (see EXEC-60)
if (!isWaiting) {
fireTimeoutOccured();
}
}
}