com.thebuzzmedia.exiftool.core.schedulers.TimerScheduler Maven / Gradle / Ivy
/**
* Copyright 2011 The Buzz Media, LLC
* Copyright 2015 Mickael Jeanroy
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.thebuzzmedia.exiftool.core.schedulers;
import com.thebuzzmedia.exiftool.Scheduler;
import java.util.Timer;
import java.util.TimerTask;
import static com.thebuzzmedia.exiftool.commons.lang.Objects.firstNonNull;
import static com.thebuzzmedia.exiftool.commons.lang.PreConditions.isPositive;
/**
* Scheduler using {@link java.util.Timer} as internal task scheduler.
*
*
*
* This scheduler should be used only for compatibility reason (this was the very first kind of scheduler
* available), instead instance of {@link com.thebuzzmedia.exiftool.core.schedulers.DefaultScheduler} should
* be used.
*/
public class TimerScheduler implements Scheduler {
/**
* Name of timer thread.
*/
private final String name;
/**
* Schedule delay.
* This delay must be strictly positive.
*/
private final long delay;
/**
* Timer Scheduler.
*/
private final Timer timer;
/**
* Pending task.
* This task should be cancel with {@link #stop()} method before any
* call to {@link #start(Runnable)} method.
*/
private TimerTask pendingTask;
/**
* Create scheduler.
* @param name Thread name.
* @param delay Delay before task execution.
* @throws IllegalArgumentException If {@code delay} is not strictly positive.
*/
public TimerScheduler(String name, long delay) {
this.name = firstNonNull(name, "ExifTool Cleanup Timer");
this.delay = isPositive(delay, "Delay must be strictly positive");
this.timer = new Timer(this.name, true);
}
@Override
public synchronized void start(Runnable runnable) {
pendingTask = new CleanupTask(runnable);
timer.schedule(pendingTask, delay);
}
@Override
public synchronized void stop() {
if (pendingTask != null) {
pendingTask.cancel();
timer.purge();
pendingTask = null;
}
}
@Override
protected void finalize() throws Throwable {
super.finalize();
stop();
timer.cancel();
}
private static class CleanupTask extends TimerTask {
private final Runnable runnable;
private CleanupTask(Runnable runnable) {
this.runnable = runnable;
}
@Override
public void run() {
runnable.run();
}
}
}