/*
* NOTE: This copyright does *not* cover user programs that use HQ
* program services by normal system calls through the application
* program interfaces provided as part of the Hyperic Plug-in Development
* Kit or the Hyperic Client Development Kit - this is merely considered
* normal use of the program, and does *not* fall under the heading of
* "derived work".
*
* Copyright (C) [2004-2009], Hyperic, Inc.
* This file is part of HQ.
*
* HQ is free software; you can redistribute it and/or modify
* it under the terms version 2 of the GNU General Public License as
* published by the Free Software Foundation. This program is distributed
* in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*/
package org.hyperic.util.thread;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Component;
/**
* This class is able to interrupt threads after a certain interval -- useful
* when threads need to have a bounded runtime.
*/
@Component
public class ThreadWatchdog {
private final Log _log = LogFactory.getLog(ThreadWatchdog.class);
private ScheduledThreadPoolExecutor _executor;
private ThreadFactory _tFact;
public ThreadWatchdog() {
_tFact = new ThreadFactory() {
public Thread newThread(Runnable r) {
return new Thread(r, "ThreadWatchdog");
}
};
}
/**
* Must be called prior to any other use of this object.
*/
@PostConstruct
public void initialize() {
_executor = new ScheduledThreadPoolExecutor(1, _tFact);
}
@PreDestroy
public final void destroy() {
this._executor.shutdownNow() ;
}//EOM
/**
* Schedule an interrupt for the current thread.
*
* @param delay The # of units to delay
* @param units Combines with 'delay' to give the length of time to
* delay
* @param targetMsg An informational message about what the current thread
* is doing, used when logging an interrupt.
*/
public InterruptToken interruptMeIn(long delay, TimeUnit units,
String targetMsg)
{
Interruptor i = new Interruptor(Thread.currentThread(), targetMsg,
delay + " " + units);
Future f;
synchronized (_executor) {
f = _executor.schedule(i, delay, units);
}
InterruptToken res = new InterruptToken(f);
return res;
}
/**
* Cancel a scheduled interrupt.
*/
public void cancelInterrupt(InterruptToken t) {
t._f.cancel(false);
}
public static class InterruptToken {
private final Future _f;
private InterruptToken(Future f) {
_f = f;
}
}
private class Interruptor
implements Runnable
{
private final Thread _target;
private final String _targetMsg;
private final String _timeMsg;
public Interruptor(Thread target, String targetMsg, String timeMsg) {
_target = target;
_targetMsg = targetMsg;
_timeMsg = timeMsg;
}
public void run() {
_log.warn("Interrupting thread [" + _target + "] (" + _targetMsg +
") it exceeded " + _timeMsg);
_target.interrupt();
}
}
}