/*
* The MIT License
*
* Copyright (c) 2011, Vojtech Juranek
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package hudson.model;
import hudson.ExtensionList;
import hudson.ExtensionPoint;
import hudson.init.Initializer;
import hudson.triggers.SafeTimerTask;
import jenkins.util.Timer;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;
import static hudson.init.InitMilestone.JOB_LOADED;
/**
* Extension point which allows scheduling a task with variable interval. Interval in evaluated every time before next
* task is scheduled by calling {@link #getRecurrencePeriod()}. Task to be scheduled is obtain by calling {@link #getNewInstance()}.
*
* <p>
* This class is similar to {@link PeriodicWork}. The main difference is in re-evaluating delay interval every time.
* See {@link PeriodicWork} for details. Analog of {@link AsyncPeriodicWork} is {@link AsyncAperiodicWork}.
*
* @author vjuranek
* @since 1.410
*/
public abstract class AperiodicWork extends SafeTimerTask implements ExtensionPoint {
protected final Logger logger = Logger.getLogger(getClass().getName());
/**
* Gets the number of milliseconds between successive executions.
*
* <p>
* Jenkins calls this method every time the timer task is scheduled.
*
*/
public abstract long getRecurrencePeriod();
/**
* Gets new instance of task to be executed. Method should return new instance each time, as there no check, if previously
* scheduled task already finished. Returning same instance could lead to throwing {@link IllegalStateException} (especially
* in case of {@link AsyncAperiodicWork}) and therefore scheduling of next tasks will be broken.
*
* @return AperiodicWork - timer task instance to be executed
*/
public abstract AperiodicWork getNewInstance();
/**
* Gets the number of milliseconds till the first execution.
*
* <p>
* By default it chooses the value randomly between 0 and {@link #getRecurrencePeriod()}
*/
public long getInitialDelay() {
long l = RANDOM.nextLong();
// Math.abs(Long.MIN_VALUE)==Long.MIN_VALUE!
if (l==Long.MIN_VALUE)
l++;
return Math.abs(l)%getRecurrencePeriod();
}
@Override
public final void doRun() throws Exception{
doAperiodicRun();
Timer.get().schedule(getNewInstance(), getRecurrencePeriod(), TimeUnit.MILLISECONDS);
}
@Initializer(after= JOB_LOADED)
public static void init() {
// start all AperidocWorks
for (AperiodicWork p : AperiodicWork.all()) {
Timer.get().schedule(p, p.getInitialDelay(), TimeUnit.MILLISECONDS);
}
}
protected abstract void doAperiodicRun();
/**
* Returns all the registered {@link AperiodicWork}s.
*/
public static ExtensionList<AperiodicWork> all() {
return ExtensionList.lookup(AperiodicWork.class);
}
private static final Random RANDOM = new Random();
}