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Ehcache is an open source, standards-based cache used to boost performance,
offload the database and simplify scalability. Ehcache is robust, proven and full-featured and
this has made it the most widely-used Java-based cache.
/**
* Copyright Terracotta, Inc.
*
* 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 net.sf.ehcache.util;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
/**
* A fail-safe timer in the sense that if the runtime environment restricts
* creating new threads, it doesn't blow up with an exception. TimerTasks that are
* scheduled will run at least once (inline when they are scheduled) if creating
* threads is not allowed.
* For example, Google App Engine does not allow creation of new threads.
*
* Clients should not use this as a general purpose timing service. To do so could
* interfere with the running of the Cache.
*
* @author Abhishek Sanoujam
* @since 1.7
*
*/
public class FailSafeTimer {
private final Timer timer;
private final boolean timerThreadRunning;
/**
* Constructor accepting a name for the timer. The scheduling thread is
* created as a daemon
*
* @param name
*/
public FailSafeTimer(String name) {
boolean threadRunning;
Timer localTimer = null;
try {
localTimer = new Timer(name, true);
threadRunning = true;
} catch (Exception e) {
localTimer = null;
threadRunning = false;
}
this.timerThreadRunning = threadRunning;
this.timer = localTimer;
}
/**
* If the runtime environment restricts thread creation, this method does
* nothing.
*
* @see java.util.Timer#cancel()
*/
public void cancel() {
if (timerThreadRunning) {
timer.cancel();
}
}
/**
* If the runtime environment restricts thread creation, this method does
* nothing.
*
* @see java.util.Timer#purge()
*/
public int purge() {
if (timerThreadRunning) {
return timer.purge();
} else {
return 0;
}
}
/**
* If the runtime environment restricts thread creation, the task is run
* inline for only one time. No further repeated execution happens for the
* task
*
* @see java.util.Timer#schedule(java.util.TimerTask, java.util.Date, long)
*/
public void schedule(TimerTask task, Date firstTime, long period) {
if (timerThreadRunning) {
timer.schedule(task, firstTime, period);
} else {
task.run();
}
}
/**
* If the runtime environment restricts thread creation, the task is run
* inline for only one time. No further repeated execution happens for the
* task
*
* @see java.util.Timer#schedule(java.util.TimerTask, java.util.Date)
*/
public void schedule(TimerTask task, Date time) {
if (timerThreadRunning) {
timer.schedule(task, time);
} else {
task.run();
}
}
/**
* If the runtime environment restricts thread creation, the task is run
* inline for only one time. No further repeated execution happens for the
* task
*
* @see java.util.Timer#schedule(java.util.TimerTask, long, long)
*/
public void schedule(TimerTask task, long delay, long period) {
if (timerThreadRunning) {
timer.schedule(task, delay, period);
} else {
task.run();
}
}
/**
* If the runtime environment restricts thread creation, the task is run
* inline for only one time. No further repeated execution happens for the
* task
*
* @see java.util.Timer#schedule(java.util.TimerTask, long)
*/
public void schedule(TimerTask task, long delay) {
if (timerThreadRunning) {
timer.schedule(task, delay);
} else {
task.run();
}
}
/**
* If the runtime environment restricts thread creation, the task is run
* inline for only one time. No further repeated execution happens for the
* task
*
* @see java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, java.util.Date, long)
*/
public void scheduleAtFixedRate(TimerTask task, Date firstTime, long period) {
if (timerThreadRunning) {
timer.scheduleAtFixedRate(task, firstTime, period);
} else {
task.run();
}
}
/**
* If the runtime environment restricts thread creation, the task is run
* inline for only one time. No further repeated execution happens for the
* task
*
* @see java.util.Timer#scheduleAtFixedRate(java.util.TimerTask, long, long)
*/
public void scheduleAtFixedRate(TimerTask task, long delay, long period) {
if (timerThreadRunning) {
timer.scheduleAtFixedRate(task, delay, period);
} else {
task.run();
}
}
}