ActiveMQ example source code file (DedicatedTaskRunner.java)

This example ActiveMQ source code file (DedicatedTaskRunner.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 - ActiveMQ tags/keywords

dedicatedtaskrunner, dedicatedtaskrunner, interruptedexception, interruptedexception, map, object, object, string, task, taskrunner, thread, thread, util

The ActiveMQ DedicatedTaskRunner.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.activemq.thread;

import org.apache.activemq.util.MDCHelper;

import java.util.Map;

/**
 * 
 */
class DedicatedTaskRunner implements TaskRunner {

    private final Task task;
    private final Thread thread;

    private final Object mutex = new Object();
    private boolean threadTerminated;
    private boolean pending;
    private boolean shutdown;

    public DedicatedTaskRunner(Task task, String name, int priority, boolean daemon) {
        this.task = task;
        final Map context = MDCHelper.getCopyOfContextMap();
        thread = new Thread(name) {
            public void run() {
                MDCHelper.setContextMap(context);
                runTask();
            }
        };
        thread.setDaemon(daemon);
        thread.setName(name);
        thread.setPriority(priority);
        thread.start();
    }

    /**
     */
    public void wakeup() throws InterruptedException {
        synchronized (mutex) {
            if (shutdown) {
                return;
            }
            pending = true;
            mutex.notifyAll();
        }
    }

    /**
     * shut down the task
     * 
     * @param timeout
     * @throws InterruptedException
     */
    public void shutdown(long timeout) throws InterruptedException {
        synchronized (mutex) {
            shutdown = true;
            pending = true;
            mutex.notifyAll();

            // Wait till the thread stops ( no need to wait if shutdown
            // is called from thread that is shutting down)
            if (Thread.currentThread() != thread && !threadTerminated) {
                mutex.wait(timeout);
            }
        }
    }

    /**
     * shut down the task
     * 
     * @throws InterruptedException
     */
    public void shutdown() throws InterruptedException {
        shutdown(0);
    }

    final void runTask() {

        try {
            while (true) {

                synchronized (mutex) {
                    pending = false;
                    if (shutdown) {
                        return;
                    }
                }

                if (!task.iterate()) {
                    // wait to be notified.
                    synchronized (mutex) {
                        if (shutdown) {
                            return;
                        }
                        while (!pending) {
                            mutex.wait();
                        }
                    }
                }

            }

        } catch (InterruptedException e) {
            // Someone really wants this thread to die off.
            Thread.currentThread().interrupt();
        } finally {
            // Make sure we notify any waiting threads that thread
            // has terminated.
            synchronized (mutex) {
                threadTerminated = true;
                mutex.notifyAll();
            }
        }
    }
}