net.timewalker.ffmq4.utils.async.AsyncTaskProcessorThread.java Source code

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Here is the source code for net.timewalker.ffmq4.utils.async.AsyncTaskProcessorThread.java

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/*
 * This file is part of FFMQ.
 *
 * FFMQ is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * FFMQ 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with FFMQ; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package net.timewalker.ffmq4.utils.async;

import java.util.concurrent.Semaphore;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * AsyncTaskProcessorThread
 */
public class AsyncTaskProcessorThread extends Thread {
    private static final Log log = LogFactory.getLog(AsyncTaskProcessorThread.class);

    // Attributes
    private AsyncTaskProcessorThreadListener listener;

    // Runtime
    private boolean stopRequired = false;
    private Semaphore waitLock = new Semaphore(0);
    private AsyncTask task;
    private boolean traceEnabled = log.isTraceEnabled();

    /**
     * Constructor
     */
    protected AsyncTaskProcessorThread(AsyncTaskProcessorThreadListener listener) {
        super("AsyncTaskProcessorThread");
        setDaemon(true);
        this.listener = listener;
    }

    /* (non-Javadoc)
     * @see java.lang.Thread#run()
     */
    @Override
    public void run() {
        try {
            while (!stopRequired) {
                if (traceEnabled)
                    log.trace("Thread entering passive wait : " + getName());

                // Passive wait
                waitLock.acquire();
                if (stopRequired)
                    break;

                // Process the container
                if (traceEnabled)
                    log.trace("Executing task " + task);

                // Execute task
                task.execute();

                // Notify listener
                listener.executionComplete(this);
            }
        } catch (Throwable ex) {
            log.error("Asynchronous execution thread failed", ex);
        }
        log.debug("Thread exits : " + getName());
    }

    /**
     * Ask the thread to execute the current task
     */
    protected void execute() {
        waitLock.release();
    }

    /**
     * Set the next task to be executed by this thread
     */
    protected void setTask(AsyncTask target) {
        this.task = target;
    }

    public void pleaseStop() {
        stopRequired = true;
        waitLock.release();
    }
}