whoami.java

有关java 的p2p应用,是一般很好的教程,有兴趣的朋友应该好好阅读一下

/*
 * 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 SUN MICROSYSTEMS 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: whoami.java,v 1.24 2006/02/07 19:01:15 bondolo Exp $
 */


package net.jxta.impl.shell.bin.whoami;

import java.util.Enumeration;
import java.util.Vector;
import java.io.StringWriter;

import net.jxta.impl.shell.ShellApp;
import net.jxta.impl.shell.ShellEnv;
import net.jxta.impl.shell.ShellObject;
import net.jxta.protocol.PeerAdvertisement;
import net.jxta.protocol.PeerGroupAdvertisement;
import net.jxta.protocol.RouteAdvertisement;
import net.jxta.peergroup.PeerGroup;
import net.jxta.document.AdvertisementFactory;
import net.jxta.document.Element;
import net.jxta.document.MimeMediaType;
import net.jxta.document.StructuredTextDocument;
import net.jxta.document.TextElement;
import net.jxta.endpoint.EndpointAddress;
import net.jxta.endpoint.EndpointService;


/**
 * whoami command list the local peer information
 */

public class whoami extends ShellApp {

    private ShellEnv myEnv;

    public whoami() {}

    public int startApp (String[] args) {

        int i = 0;
        boolean full = false;
        boolean viewpg = false;
        ShellObject obj =  null;
        PeerGroup pg =  null;
        PeerGroupAdvertisement groupAdv = null;
        PeerAdvertisement peerAdv = null;

        myEnv = getEnv();

        if (args != null) {
            for (i=0; i < args.length; ++i) {
                if (args[i].equals("-l")) {
                    full = true;
                    continue;
                }
                if (args[i].equals("-g")) {
                    viewpg = true;
                    continue;
                }
                return syntaxError();
            }
        }

        if (viewpg) { // Select the default peerGroup
            obj = myEnv.get ("stdgroup");
        } else {
            obj = myEnv.get ("rootgroup");
            if (obj == null) // we really want the netpeergroup
                obj = myEnv.get ("stdgroup");
        }

        // extract the advertisement
        pg = (PeerGroup) obj.getObject();
        groupAdv = pg.getPeerGroupAdvertisement();
        peerAdv = pg.getPeerAdvertisement();
        Enumeration endps = getEndpointAddresses (peerAdv);

        if( full ) {
            println(peerAdv.toString());
        } else if (!viewpg ) {
            String name = peerAdv.getName();
            if (name != null)
                println("<Peer>"+name+"</Peer>");
            String desc = peerAdv.getDescription();
            if (desc != null)
                println("<Description>" + desc +"</Description>");
            println("<PeerId>"+ peerAdv.getPeerID()+"</PeerId>");

            if (endps != null) {
                while (endps.hasMoreElements()) {
                    try {
                        EndpointAddress endp = (EndpointAddress)
                                               endps.nextElement();
                        println("<TransportAddress>"+ endp.toString() +
                                "</TransportAddress>");
                    } catch (Exception ez1) {
                        // Not much can be done here
                    }
                }
            }
        } else {
            println("<PeerGroup>"+
                    groupAdv.getName()+"</PeerGroup>");
            String desc = groupAdv.getDescription();
            if (desc != null)
                println("<Description>"+desc+"</Description>");
            println("<PeerGroupId>"+
                    groupAdv.getPeerGroupID()+"</PeerGroupId>");

            /************ BEGINING OF COMMENTED OUT CODE
             ** [e-mail]: I'm commenting the following out, because it does not
             ** seem that the current peergroup adv implementation allows to recover
             ** all the service advertisement (unless, of course, you know the ID, which is
             ** not the case here)
             ** 
             ** This will have to be taken care of as soon as possible.

                   for (Enumeration e=groupAdv.getServiceAdvertisements().
              elements(); e.hasMoreElements();) {
                       ServiceAdvertisement p
                           = (ServiceAdvertisement) e.nextElement();
                       println("<Service>" + p.getName() + "</Service>");
                   }

            ****************************** END OF COMMENTED OUT CODE */
        }

        return ShellApp.appNoError;
    }

    private Enumeration getEndpointAddresses (PeerAdvertisement peerAdv) {

        // Get its EndpointService advertisement
        TextElement endpParam = (TextElement)
                                peerAdv.getServiceParam(PeerGroup.endpointClassID);

        if (endpParam == null) {
            return null;
        }

        RouteAdvertisement route = null;
        try {
            Enumeration paramChilds = endpParam.getChildren(
                                          RouteAdvertisement.getAdvertisementType());
            Element param = null;

            if( paramChilds.hasMoreElements() ) {
                param = (Element) paramChilds.nextElement();
            }
            route = (RouteAdvertisement)
                    AdvertisementFactory.newAdvertisement((TextElement)param);
        } catch (Exception ex) {
            return null;
        }

        if (route == null) {
            return null;
        }

        EndpointService endpoint = getGroup().getEndpointService();
        Vector addrs = new Vector();
        try {
            for (Enumeration e = route.getDest().getEndpointAddresses();
                    e.hasMoreElements(); ) {
                addrs.addElement(new EndpointAddress((String)
                                                     e.nextElement()));
            }
        } catch (Exception e) {
            return null;
        }

        if (addrs.size() == 0) {
            return null;
        }

        return addrs.elements();
    }


    public int syntaxError() {
        println ("error: whoami [-g] [-l]");
        return ShellApp.appParamError;
    }


    public void stopApp () {}

    public String getDescription() {
        return "Display information about a peer or peergroup";
    }

    public void help() {
        println("NAME");
        println("     whoami - display information about a peer or peergroup");
        println(" ");
        println("SYNOPSIS");
        println("     whoami [-l] [-g]");
        println(" ");
        println("DESCRIPTION");
        println(" ");
        println("whoami displays information about a peer or a");
        println("peergroup. With no option, whoami returns");
        println("information about the local peer. The '-g' option returns");
        println("information about the current peer group joined.");
        println("");
        println("By default the Shell is brought up in the 'NetPeerGroup' group. " );
        println("Only the peerId and the peerGroup ID are guaranteed");
        println("to be unique.");
        println("");
        println("OPTIONS");
        println("");
        println("     [-g]  return info about the current peergroup");
        println("     [-l]  return a long version of the advertisement");
        println(" ");
        println("EXAMPLE");
        println(" ");
        println("    JXTA>whoami -l");
        println(" ");
        println("This example displays a long version of the peer group information");
        println(" ");
        println("SEE ALSO");
        println("    peers");
    }
}