Commons IO example source code file (ThreadMonitor.java)

This example Commons IO source code file (ThreadMonitor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons IO tags/keywords

interruptedexception, interruptedexception, runnable, runnable, thread, thread, threadmonitor, threadmonitor

The Commons IO ThreadMonitor.java source code

/*
 * 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()
 * the <i>monitor 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
     * 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
     * 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
     */
    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
        }
    }
}