wirepipe.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

/*
 *
 * $Id: WirePipe.java,v 1.40 2006/08/10 19:45:07 bondolo Exp $
 *
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
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 * 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
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 * 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
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 * ====================================================================
 *
 * 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.
 */

package net.jxta.impl.pipe;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.WeakHashMap;

import net.jxta.document.MimeMediaType;
import net.jxta.document.StructuredDocumentFactory;
import net.jxta.document.XMLDocument;
import net.jxta.endpoint.EndpointAddress;
import net.jxta.endpoint.EndpointListener;
import net.jxta.endpoint.Message;
import net.jxta.endpoint.MessageElement;
import net.jxta.endpoint.TextDocumentMessageElement;
import net.jxta.id.ID;
import net.jxta.impl.cm.SrdiIndex;
import net.jxta.impl.id.UUID.UUID;
import net.jxta.impl.id.UUID.UUIDFactory;
import net.jxta.peergroup.PeerGroup;
import net.jxta.pipe.InputPipe;
import net.jxta.pipe.PipeService;
import net.jxta.protocol.PipeAdvertisement;
import net.jxta.rendezvous.RendezVousService;

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

/**
 * WirePipe (aka Propagated pipe) is very similar to IGMP, where a creation of an
 * input pipe results in a propagated pipe membership registration with the peer's
 * rendezvous peer, and a closure results in a propagated pipe group resignation,
 * these group registration/resignation are simply PipeService SRDI messages.
 */
public class WirePipe implements EndpointListener, InputPipe, PipeRegistrar {

    /**
     *  Log4J Logger
     */
    private final static transient Logger LOG = Logger.getLogger(WirePipe.class.getName());

    private static final int MAX_RECORDED_MSGIDS = 250;

    private volatile boolean closed = false;

    private PeerGroup myGroup = null;
    private PipeResolver pipeResolver = null;
    private WirePipeImpl pipeService = null;
    private PipeAdvertisement pipeAdv = null;

    private RendezVousService rendezvous = null;
    private final String localPeerId;
    private NonBlockingWireOutputPipe repropagater = null;

    /**
     *  Table of local input pipes listening on this pipe. Weak map so that
     *  we don't keep pipes unnaturally alive and consuming resources.
     *
     *  <p/><ul>
     *      <li>Values are {@link net.jxta.pipe.InputPipe}.</li>
     *  </ul>
     */
    private Map wireinputpipes = new WeakHashMap();

    /**
     *  Count of the number of local input pipes. Though it's mostly the same we
     *  can't use <code>wireinputpipes.size()</code> because it's too twitchy.
     *  We can guarantee that this field's value will change in predictable ways.
     */
    private int nbInputPipes = 0;

    /**
     *  The list of message ids we have already seen. The most recently seen
     *  messages are at the end of the list.
     *
     *  <p/>XXX 20031102 [e-mail]: We might want to consider three
     *  performance enhancements:
     *
     *  <ul>
     *      <li>Reverse the order of elements in the list. This would result
     *      in faster searching since the default strategy for ArrayList to
     *      search in index order. We are most likely to see duplicate messages
     *      amongst the messages we have seen recently. This would make
     *      additions more costly.</li>
     *
     *      <li>When we do find a duplicate in the list, exchange it's location
     *      with the newest message in the list. This will keep annoying dupes
     *      close to the start of the list.</li>
     *
     *      <li>When the array reaches MaxNbOfStoredIds treat it as a ring.</li>
     *  </ul>
     */
    private final List<UUID> msgIds = new ArrayList<UUID>(MAX_RECORDED_MSGIDS);

    /**
     * Constructor
     *
     * @param g The Group associated with this service
     * @param pipeResolver the associated pipe resolver
     * @param pipeService The pipe service associated with this pipe
     * @param adv pipe advertisement
     */
    public WirePipe(PeerGroup g,
                    PipeResolver pipeResolver,
                    WirePipeImpl pipeService,
                    PipeAdvertisement adv) {

        this.myGroup = g;
        this.pipeResolver = pipeResolver;
        this.pipeService = pipeService;
        this.pipeAdv = adv;
        localPeerId = myGroup.getPeerID().toString();
        rendezvous = g.getRendezVousService();
        pipeResolver.register(this);
        repropagater = pipeService.createOutputPipe(adv, Collections.EMPTY_SET);
    }

    /**
     *  {@inheritDoc}
     *
     *  <p/>Closes the pipe.
     */
    protected synchronized void finalize() throws Throwable {

        if(!closed) {
            if (LOG.isEnabledFor(Level.WARN)) {
                LOG.warn("Pipe is being finalized without being previously closed. This is likely a bug.");
            }
        }
        close();
        super.finalize();
    }

    /**
     *  {@inheritDoc}
     */
    public synchronized boolean register(InputPipe wireinputpipe) {
        wireinputpipes.put(wireinputpipe, null);

        nbInputPipes++;
        if(1 == nbInputPipes) {
            if (LOG.isEnabledFor(Level.INFO)) {
                LOG.info("Registering wire pipe with SRDI");
            }

            boolean registered = myGroup.getEndpointService().addIncomingMessageListener((EndpointListener) wireinputpipe, "PipeService", wireinputpipe.getPipeID().toString());

            if(!registered) {
                if (LOG.isEnabledFor(Level.WARN)) {
                    LOG.warn("Existing Registered Endpoint Listener for " + wireinputpipe.getPipeID());
                }
            }

            pipeResolver.pushSrdi(this, true);
        }

        return true;
    }

    /**
     *  {@inheritDoc}
     */
    public synchronized boolean forget(InputPipe wireinputpipe) {
        wireinputpipes.remove(wireinputpipe);

        nbInputPipes--;
        if(0 == nbInputPipes) {
            if (LOG.isEnabledFor(Level.INFO)) {
                LOG.info("Deregistering wire pipe with SRDI");
            }
            pipeResolver.pushSrdi(this, false);

            EndpointListener removed = myGroup.getEndpointService().removeIncomingMessageListener("PipeService", wireinputpipe.getPipeID().toString());

            if((null == removed) || (this != removed)) {
                if (LOG.isEnabledFor(Level.WARN)) {
                    LOG.warn("removeIncomingMessageListener() did not remove correct pipe!");
                }
            }
        }

        if(nbInputPipes < 0) {
            // we reset this to zero so that re-registration works.
            nbInputPipes = 0;

            if (LOG.isEnabledFor(Level.WARN)) {
                LOG.warn("Number of pipe listeners was < 0");
            }
        }

        return true;
    }

    // This is the InputPipe API implementation.
    // This is needed only to be able to register an InputPipe to the PipeResolver.
    // Not everything has to be implemented.

    /**
     *  {@inheritDoc}
     */
    public Message waitForMessage() throws InterruptedException {
        if (LOG.isEnabledFor(Level.DEBUG)) {
            LOG.debug("This method is not really supported.");
        }
        return null;
    }

    /**
     *  {@inheritDoc}
     */
    public Message poll(int timeout) throws InterruptedException {
        if (LOG.isEnabledFor(Level.DEBUG)) {
            LOG.debug("This method is not really supported.");
        }

        return null;
    }