gistfile1.java

public final class Scheduler extends ServiceSupport {

    private final String name;
    private Timer timer;
    private final HashMap<Runnable, TimerTask> timerTasks = new HashMap<Runnable, TimerTask>();

    public Scheduler(String name) {
        this.name = name;
    }

    public synchronized void executePeriodically(final Runnable task, long period) {
        TimerTask timerTask = new SchedulerTimerTask(task);
        timer.schedule(timerTask, period, period);
        timerTasks.put(task, timerTask);
    }

    public synchronized void cancel(Runnable task) {
        TimerTask ticket = timerTasks.remove(task);
        if (ticket != null) {
            ticket.cancel();
            timer.purge(); // remove cancelled TimerTasks
        }
    }

    public synchronized void executeAfterDelay(final Runnable task, long redeliveryDelay) {
        TimerTask timerTask = new SchedulerTimerTask(task);
        timer.schedule(timerTask, redeliveryDelay);
    }

    public void shutdown() {
        timer.cancel();
    }

    @Override
    protected synchronized void doStart() throws Exception {
        this.timer = new Timer(name, true);
    }

    @Override
    protected synchronized void doStop(ServiceStopper stopper) throws Exception {
        if (this.timer != null) {
            this.timer.cancel();
        }
    }

    public String getName() {
        return name;
    }

}