org.phoebus.applications.alarm.ResettableTimeout Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2018-2023 Oak Ridge National Laboratory.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*******************************************************************************/
package org.phoebus.applications.alarm;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import org.phoebus.framework.jobs.NamedThreadFactory;
/** Reset-able timeout
*
* Meant for one-time use:
* Timeout is started.
* While running, it may be reset several times.
* Eventually, if there are no more resets,
* it will time out.
*
* Timeout can be adjusted on each 'reset'
*
* @author Kay Kasemir
*/
@SuppressWarnings("nls")
public class ResettableTimeout
{
private long timeout_secs;
private final ScheduledExecutorService timer = Executors.newSingleThreadScheduledExecutor(new NamedThreadFactory("ResettableTimeout"));
private final CountDownLatch no_more_messages = new CountDownLatch(1);
private final Runnable signal_no_more_messages = () -> no_more_messages.countDown();
private final AtomicReference> timeout = new AtomicReference<>();
/** @param timeout_secs Seconds after which we time out */
public ResettableTimeout(final long timeout_secs)
{
this.timeout_secs = timeout_secs;
reset();
}
/** Reset the timer. As long as this is called within the timeout, we keep running
* @param timeout_secs New timeout in seconds
*/
public void reset(final long timeout_secs)
{
this.timeout_secs = timeout_secs;
reset();
}
/** Reset the timer. As long as this is called within the timeout, we keep running */
public void reset()
{
final ScheduledFuture previous = timeout.getAndSet(timer.schedule(signal_no_more_messages, timeout_secs, TimeUnit.SECONDS));
if (previous != null)
previous.cancel(false);
}
/** Waits for a timeout, i.e. no 'reset' within the timeout
*
* @param seconds Seconds to wait for a timeout
* @return true if timed out, otherwise (after waiting for 'seconds'), returns false
*/
public boolean awaitTimeout(final long seconds)
{
try
{
return no_more_messages.await(seconds, TimeUnit.SECONDS);
}
catch (InterruptedException ex)
{
}
return false;
}
/** Release resources */
public void shutdown()
{
final ScheduledFuture previous = timeout.getAndSet(null);
if (previous != null)
previous.cancel(false);
timer.shutdown();
}
}