/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.commons.io;
/**
* Monitors a thread, interrupting it of it reaches the specified timout.
* <p>
* This works by sleeping until the specified timout amount and then
* interrupting the thread being monitored. If the thread being monitored
* completes its work before being interrupted, it should <code>interrupt()<code>
* the <i>monitor</i> thread.
* <p>
*
* <pre>
* long timeoutInMillis = 1000;
* try {
* Thread monitor = ThreadMonitor.start(timeoutInMillis);
* // do some work here
* ThreadMonitor.stop(monitor);
* } catch (InterruptedException e) {
* // timed amount was reached
* }
* </pre>
*
* @version $Id: ThreadMonitor.java 1002689 2010-09-29 15:43:48Z niallp $
*/
class ThreadMonitor implements Runnable {
private final Thread thread;
private final long timeout;
/**
* Start monitoring the current thread.
*
* @param timeout The timout amount in milliseconds
* or no timeout if the value is zero or less
* @return The monitor thread or <code>null</code>
* if the timout amount is not greater than zero
*/
public static Thread start(long timeout) {
return start(Thread.currentThread(), timeout);
}
/**
* Start monitoring the specified thread.
*
* @param thread The thread The thread to monitor
* @param timeout The timout amount in milliseconds
* or no timeout if the value is zero or less
* @return The monitor thread or <code>null</code>
* if the timout amount is not greater than zero
*/
public static Thread start(Thread thread, long timeout) {
Thread monitor = null;
if (timeout > 0) {
ThreadMonitor timout = new ThreadMonitor(thread, timeout);
monitor = new Thread(timout, ThreadMonitor.class.getSimpleName());
monitor.setDaemon(true);
monitor.start();
}
return monitor;
}
/**
* Stop monitoring the specified thread.
*
* @param thread The monitor thread, may be <code>null</code>
*/
public static void stop(Thread thread) {
if (thread != null) {
thread.interrupt();
}
}
/**
* Construct and new monitor.
*
* @param thread The thread to monitor
* @param timeout The timout amount in milliseconds
*/
private ThreadMonitor(Thread thread, long timeout) {
this.thread = thread;
this.timeout = timeout;
}
/**
* Sleep until the specified timout amount and then
* interrupt the thread being monitored.
*
* @see Runnable#run()
*/
public void run() {
try {
Thread.sleep(timeout);
thread.interrupt();
} catch (InterruptedException e) {
// timeout not reached
}
}
}
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