discoveryserver.java

jxta的例子

/*
 * Copyright (c) 2001-2007 Sun Microsystems, Inc.  All rights reserved.
 *  
 *  The Sun Project JXTA(TM) Software License
 *  
 *  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.
 *  
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 *     and/or other materials provided with the distribution.
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 *  3. The end-user documentation included with the redistribution, if any, must 
 *     include the following acknowledgment: "This product includes software 
 *     developed by Sun Microsystems, Inc. for JXTA(TM) technology." 
 *     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.
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 *  5. Products derived from this software may not be called "JXTA", nor may 
 *     "JXTA" appear in their name, without prior written permission of Sun.
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 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
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 *  JXTA is a registered trademark of Sun Microsystems, Inc. in the United 
 *  States and other countries.
 *  
 *  Please see the license information page at :
 *  <http://www.jxta.org/project/www/license.html> for instructions on use of 
 *  the license in source files.
 *  
 *  ====================================================================
 *  
 *  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 tutorial.discovery;


import net.jxta.discovery.DiscoveryEvent;
import net.jxta.discovery.DiscoveryListener;
import net.jxta.discovery.DiscoveryService;
import net.jxta.document.Advertisement;
import net.jxta.document.AdvertisementFactory;
import net.jxta.id.IDFactory;
import net.jxta.peergroup.PeerGroup;
import net.jxta.peergroup.PeerGroupID;
import net.jxta.pipe.PipeService;
import net.jxta.platform.NetworkManager;
import net.jxta.protocol.DiscoveryResponseMsg;
import net.jxta.protocol.PipeAdvertisement;

import java.io.File;
import java.util.Enumeration;


/**
 * Illustrates the use of Discovery Service
 * Note this is for illustration purposes and is not meant as a blue-print
 */
public class DiscoveryServer implements DiscoveryListener {

    private transient NetworkManager manager;
    private transient DiscoveryService discovery;

    /**
     * Constructor for the DiscoveryServer
     */
    public DiscoveryServer() {
        try {
            manager = new NetworkManager(NetworkManager.ConfigMode.ADHOC, "DiscoveryServer",
                    new File(new File(".cache"), "DiscoveryServer").toURI());
            manager.startNetwork();
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(-1);
        }
        PeerGroup netPeerGroup = manager.getNetPeerGroup();

        // get the discovery service
        discovery = netPeerGroup.getDiscoveryService();
    }

    /**
     * main
     *
     * @param args command line args
     */
    public static void main(String args[]) {
        DiscoveryServer disocveryServer = new DiscoveryServer();
        disocveryServer.start();
    }

    /**
     * create a new pipe adv, publish it for 2 minut network time,
     * sleep for 3 minutes, then repeat
     */
    public void start() {
        long lifetime = 60 * 2 * 1000L;
        long expiration = 60 * 2 * 1000L;
        long waittime = 60 * 3 * 1000L;

        try {
            while (true) {
                PipeAdvertisement pipeAdv = getPipeAdvertisement();

                // publish the advertisement with a lifetime of 2 mintutes
                System.out.println(
                        "Publishing the following advertisement with lifetime :" + lifetime + " expiration :" + expiration);
                System.out.println(pipeAdv.toString());
                discovery.publish(pipeAdv, lifetime, expiration);
                discovery.remotePublish(pipeAdv, expiration);
                try {
                    System.out.println("Sleeping for :" + waittime);
                    Thread.sleep(waittime);
                } catch (Exception e) {// ignored
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * This method is called whenever a discovery response is received, which are
     * either in response to a query we sent, or a remote publish by another node
     *
     * @param ev the discovery event
     */
    public void discoveryEvent(DiscoveryEvent ev) {

        DiscoveryResponseMsg res = ev.getResponse();

        // let's get the responding peer's advertisement
        System.out.println(" [  Got a Discovery Response [" + res.getResponseCount() + " elements]  from peer : " + ev.getSource() + "  ]");

        Advertisement adv;
        Enumeration en = res.getAdvertisements();

        if (en != null) {
            while (en.hasMoreElements()) {
                adv = (Advertisement) en.nextElement();
                System.out.println(adv);
            }
        }
    }

    /**
     * Creates a pipe advertisement
     *
     * @return a Pipe Advertisement
     */
    public static PipeAdvertisement getPipeAdvertisement() {
        PipeAdvertisement advertisement = (PipeAdvertisement)
                AdvertisementFactory.newAdvertisement(PipeAdvertisement.getAdvertisementType());

        advertisement.setPipeID(IDFactory.newPipeID(PeerGroupID.defaultNetPeerGroupID));
        advertisement.setType(PipeService.UnicastType);
        advertisement.setName("Discovery tutorial");
        return advertisement;
    }

    /**
     * Stops the platform
     */
    public void stop() {
        // Stop JXTA
        manager.stopNetwork();
    }
}