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Date: Tue, 26 Feb 2013 06:32:28 -0800 (PST)
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Subject: Concurrency and restarting tasks
From: me 2 <winona_whitener@yahoo.com>
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Xref: csiph.com comp.lang.java.programmer:22527

Hey,

I have an interesting (to me at least!) puzzle.

I have a task that can take a long time that I need to run periodically.  I=
 want to be able to cancel the execution of that task.  I've been looking a=
t the Scheduler and Future objects, but I haven't seen how to cleanly stop,=
 wait for a couple of seconds and restart the task on schedule.  And my tas=
k won't always take X seconds--sometimes it will generate exceptions or tak=
e longer or shorter or any number of other things.

Right now I have:

<code>
		final Runnable beeper =3D new Runnable()
		{
			public void run()
			{
				System.out.println("beep -- doing long task");
				//doing long task
				System.out.println("finished doing long task");
			}
		};

			ScheduledFuture<?> beeperHandle;
			try {
				beeperHandle =3D scheduler.scheduleAtFixedRate(	beeper, 1, 2, SECONDS);
				beeperHandle.get(3, SECONDS);
			} catch (TimeoutException te) {
				System.out.println("Canceled due to timeout");
			} catch (InterruptedException | ExecutionException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
</code>

There are plenty of examples that show the first steps--setting up the sche=
dule and canceling.  Restarting apparently is not as common.

Any ideas would be fantastic.
Thank you,
Me