非活动用户的Java超时

Question

I have a problem with the ScheduledThreadPoolExecutor .

I need a timeout which will redirect to the first page after 'n'-seconds . If the user enters a character, the timer should start counting again and may not redirect to the first page. (So the counter should abort his scheduled Task)

The Problem is, that the Timer starts, but it doesn't cancel the scheduled Task if a key was typed. The stop() - Method will be called. But scheduledThreadPool.shutdownNow(); seems not to work.

My TimerClass looks like this:

public class MyTimer {

    private final Runnable logicalWorker;

    private final long delay;

    private final ScheduledThreadPoolExecutor scheduledThreadPool;

    public MyTimer(final Runnable logicalWorker, final long delay) {
        scheduledThreadPool = new ScheduledThreadPoolExecutor(1);
        this.logicalWorker = logicalWorker;
        this.delay = delay;
    }

    public void start() {
        scheduledThreadPool.schedule(logicalWorker, delay, TimeUnit.SECONDS);
    }

    public void stop() {
        scheduledThreadPool.shutdownNow();
        scheduledThreadPool.getQueue().clear();
    }

    public void restart() {
        start();
    }

    public boolean isScheduled() {
        return !scheduledThreadPool.isTerminated() && !scheduledThreadPool.isShutdown();
    }
}

The method in a superclass which calls the timerClass is this one:

protected void startTimeout() {
    if (currentInstance.getAutoTimeout() != null && currentInstance.getAutoTimeout().isScheduled()) {
        currentInstance.getAutoTimeout().restart();
        return;
    }
    currentInstance.setAutoTimeout(new MyTimer(new Runnable() {

        @Override
        public void run() {
            Platform.runLater(new Runnable() {

                @Override
                public void run() {
                    if (!PageContent.PAGE_ID.equals(currentInstance.getPageId()) && !forceOpen) {
                        cancelCurrentProcesses();
                        switchPageByPageId(PageContent.PAGE_ID);
                    }
                }
            });
        }
    }, currentInstance.getPageDelay()));
    if (currentInstance.getPageDelay() > 0) {
        currentInstance.getAutoTimeout().start();
    }
}

The KeyListener and the MouseClickListener will be set on the scene at the beginning by this method:

protected void placePage() throws SecurityException, IllegalArgumentException, IllegalAccessException,
        InstantiationException, NoSuchMethodException, InvocationTargetException {
    startTimeout();
    currentInstance.getRoot().setOnMouseClicked(new EventHandler<MouseEvent>() {

        @Override
        public void handle(MouseEvent arg0) {
            startTimeout();
        }
    });
    currentInstance.getRoot().setOnKeyReleased(new EventHandler<KeyEvent>() {

        @Override
        public void handle(KeyEvent arg0) {
            startTimeout();
        }
    });
}

Answer 1

Take a look at this -> http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ScheduledThreadPoolExecutor.html

The shutdownNow() makes no guarantees to cancel execution.

As for a solution, I recommend you use ScheduledFuture or Future objects rather than Runnable .

[EDIT] A scheduled future, on which you can call a .cancel() function instead of .shutdownNow() is returned by the .schedule() call, which you call, but don't seem to use (or indeed save) the handle to the Future anywhere. And yes, you do still need a Runnable but only insofar as it will give you the Future handle.

Try something like this:

private ScheduledFuture<?> future;
public void start() {
    future = scheduledThreadPool.schedule(logicalWorker, delay, TimeUnit.SECONDS);
}
public void stop() {
    if(future != null) future.cancel();
}

[/EDIT]

More details here -> http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ScheduledFuture.html