messageprocessor.java

jxta-cms-src-2.4.zip 是官网上的比较稳定的CMS源代码。目前是最稳定的高版本。

/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: MessageProcessor.java,v 1.8 2006/02/07 20:43:50 bondolo Exp $
 *
 */

package net.jxta.share;

import java.util.Vector;

import net.jxta.pipe.PipeService;
import net.jxta.endpoint.EndpointService;
import net.jxta.endpoint.Message;
import net.jxta.protocol.PipeAdvertisement;

import org.apache.log4j.Logger;
import org.apache.log4j.Level;

/**
 *  The MessageProcessor class is the abstract parent of any class, such as ListMessageProcessor, 
 *  which processes a queues of Messages for the ContentManagementService.
 */

public abstract class MessageProcessor implements Runnable {

    private final static transient Logger LOG = Logger.getLogger(MessageProcessor.class.getName());

    private CMS cms = null;
    private Vector messages = new Vector();

    public MessageProcessor(CMS inCMS) {
        cms = inCMS;

        Thread thread = new Thread(this);
        thread.start();
    }

    public EndpointService getEndpointService() {
        return cms.getEndpointService();
    }

    public String getEndpointAddress() {
        return cms.getEndpointAddress();
    }

    public ContentManager getContentManager() {
        return cms.getContentManager();
    }

    public void run() {
        Message message = null;
        while (true) {
            try {
                message = pop();
            } catch (InterruptedException e) {
                if (LOG.isEnabledFor(Level.ERROR))
                    LOG.error("could not pop message");
                break;
            }

            if (message != null) {
                process(message);
            }
        }
    }

    public synchronized void push(Message message) {
        boolean shouldNotify = (messages.size() == 0);

        // add the message to the end of the vector
        messages.addElement(message);

        if (shouldNotify) {
            // notify the thread
            notify();
        }
    }

    private synchronized Message pop()
    throws InterruptedException {
        Message message = null;

        if (messages.size() == 0) {
            // wait for an element
            wait();
        }

        // pop the first element off of the vector
        if (messages.size() > 0) {
            message = (Message)messages.firstElement();
            messages.removeElementAt(0);
        }

        return message;
    }

    protected abstract void process(Message message);
}