talk.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

                        }
                    }
                } catch(Exception e) {
                    continue;
                }

                if (checkUserAdv(adv, name)) {
                    return adv;
                }
            }
        } catch (Exception e) {}

        // Now, search remote


        discovery.getRemoteAdvertisements(null,
                                          DiscoveryService.ADV,
                                          PipeAdvertisement.NameTag,
                                          TalkNameTag + "." + name,
                                          2,
                                          this);

        // Wait a bit in order to get an answer.

        int i=0;
        while (true) {
            try {
                if (i>MAXRETRIES) {
                    println("");
                    break;
                }

                Thread.sleep( WaitingTime);
                print(".");
                i++;
                //one more query
                if (i == MAXRETRIES/2) {
                    discovery.getRemoteAdvertisements(null,
                                                      DiscoveryService.ADV,
                                                      PipeAdvertisement.NameTag,
                                                      TalkNameTag + "." + name,
                                                      2,
                                                      this);
                }
            } catch (Exception e) {}

            try {
                synchronized(this) {
                    if (results != null) {
                        Iterator eachAdv = results.iterator();
                        while( eachAdv.hasNext() ) {
                            try {
                                PipeAdvertisement adv = (PipeAdvertisement) eachAdv.next();
                                if (checkUserAdv(adv, name)) {
                                    return adv;
                                }
                            } catch(Exception e) {
                                continue;
                            }
                        }
                        results.clear();
                    }
                }
            } catch (Exception e) {}
        }

        return null;
    }

    private void runDeamon(String name, PipeAdvertisement adv) {

        userAdv = adv;
        userName = name;

        try {
            pipeIn = getGroup().getPipeService().createInputPipe(userAdv);
        } catch (Exception ex) {
            printStackTrace( "Could not open InputPipe for " + userAdv.getPipeID(), ex );
            return ;
        }

        if (pipeIn == null) {
            consoleMessage( "Could not open InputPipe for " + userAdv.getPipeID() );
            return;
        }

        thread = new Thread(this, "Talk:Talk Deamon for " + name +"@"+getGroup().getPeerGroupName() );
        thread.setDaemon( true );
        thread.start();

        ShellObject daemon = new CleanupShellObject( "Talk Deamon for : " + name +"@"+getGroup().getPeerGroupName(), this );

        // Store this object
        env.add( EnvName + "." + name +"@"+getGroup().getPeerGroupName(), daemon );
    }

    /**
     *  Stops the talk daemon thread
     **/
    private static class CleanupShellObject extends ShellObject {

        CleanupShellObject( String name, Object object ) {
            super( name, object );
        }

        /**
         *  {@inheritDoc}
         *
         *  <p/>Closes the pipe if it is still open.
         **/
        protected void finalize() throws Throwable {
            super.finalize();

            talk daemon = (talk) getObject();

            synchronized( daemon ) {
                if( null != daemon.pipeIn ) {
                    daemon.pipeIn.close();
                }
            }
        }
    }

    private void stopDeamon(String name) {

        // full name is required to find the object
        String dname = EnvName + "." + name + "@" + getGroup().getPeerGroupName();

        ShellObject obj = env.get(dname);
        if (obj == null) {
            // Notify user that the logout failed
            consoleMessage( "Daemon(" + dname + ") for " + name + " not found");
            return;
        }

        try {
            talk daemon = (talk) obj.getObject();
            env.remove(dname);
            synchronized( daemon ) {
                if( null != daemon.pipeIn ) {
                    daemon.pipeIn.close();
                }
            }
        } catch (Exception e) {
            printStackTrace("Could not stop deamon for " + name, e);
            return;
        }
    }

    /**
     *  {@inheritDoc}
     **/
    public void run() {

        try {
            // Listen on the pipe
            while (true) {
                Message msg = null;
                try {
                    msg = pipeIn.waitForMessage();

                    if( null == msg ) {
                        consoleMessage( "Stop listening for " + userName );
                        break;
                    }
                } catch ( InterruptedException woken ) {
                    Thread.interrupted();
                    consoleMessage( "Stop listening for " + userName );
                    return;
                }

                String senderName = null;

                // Get sender information
                MessageElement nameEl = msg.getMessageElement(SenderName);
                if (nameEl != null) {
                    senderName = nameEl.toString();
                } else {
                    println("received an unknown message");
                    continue;
                }

                if( null == senderName ) {
                    senderName = "Anonymous";
                }

                String senderMessage = null;
                MessageElement msgEl = msg.getMessageElement(SenderMessage);
                if (msgEl != null) {
                    senderMessage = msgEl.toString();
                } else {
                    println("received an unknown message");
                    continue;
                }

                senderMessage += handleImageFromMsg(senderName, msg);

                // Get message
                if (senderMessage == null) {
                    consoleMessage( senderName + " to " + userName + "> [empty message]" );
                    continue;
                }
                consoleMessage(senderName + " to "+ userName + "> "+senderMessage);
            }
        } catch( Throwable all ) {
            printStackTrace( "Uncaught Throwable in thread :" + Thread.currentThread().getName(), all );
        } finally {
            synchronized( this ) {
                pipeIn = null;
                thread = null;
            }
        }
    }
    /**
     * Generate uniquePipeID that is independantly unique within a group
     *
     * @return    The uniquePipeID value
     */
    private PipeAdvertisement getMyJxtaPipeAdv() {

        byte [] preCookedPID = {
                                   (byte) 0xD1, (byte) 0xD1, (byte) 0xD1, (byte) 0xD1,
                                   (byte) 0xD1, (byte) 0xD1, (byte) 0xD1, (byte) 0xD1,
                                   (byte) 0xD1, (byte) 0xD1, (byte) 0xD1, (byte) 0xD1,
                                   (byte) 0xD1, (byte) 0xD1, (byte) 0xD1, (byte) 0xD1 };

        PipeID id= (PipeID) IDFactory.newPipeID(getGroup().getPeerGroupID(), preCookedPID);
        PipeAdvertisement pipeAdv = (PipeAdvertisement)
                                    AdvertisementFactory.newAdvertisement(
                                        PipeAdvertisement.getAdvertisementType());

        pipeAdv.setPipeID(id);
        pipeAdv.setName("JXME chat demo");
        pipeAdv.setType(PipeService.PropagateType);
        return pipeAdv;

    }

    private int syntaxError() {

        consoleMessage( getDescription() );
        println("Usage: talk -[r]egister <userName> [-[s]ecure | -[p]ropagate]");
        println("       talk -[l]ogin <userName> ");
        println("       talk -[lo]gout <userName> ");
        println("       talk -[u] <senderName> <userName> ");
        println("       talk -search || -f <userName>");

        return ShellApp.appParamError;
    }

    /**
     *  {@inheritDoc}
     **/
    public String getDescription() {
        return "Talk to another peer";
    }

    /**
     *  {@inheritDoc}
     **/
    public void help() {
        println("NAME");
        println("     talk - " + getDescription() );
        println(" ");
        println("SYNOPSIS");
        println(" ");
        println("    talk -[r]egister <userName> [-[s]ecure | -[p]ropagate]");
        println("    talk -[l]ogin <userName> ");
        println("    talk -[lo]gout <userName> ");
        println("    talk -[u] <senderName> <userName> ");
        println("    talk -search || -f");
        println(" ");
        println("DESCRIPTION");
        println(" ");
        println("The 'talk command implements a simple instant messaging command");
        println("where two users on two remote peers can exchange messages.");
        println("Messages are displayed on the Shell stdout. In order");
        println("to use 'talk' the user needs to register himself. This is done");
        println("via the following steps:");
        println("Step 1: Register via 'talk -register <username>' command. This command");
        println("        creates a Talk advertisement for that user. This has to");
        println("        be done only once, the first time the user registers with");
        println("        talk. The system remembers it accross reboot.");
        println("        -secure can be added in order to establish a secure talk session.");
        println("        -propagate can be added in order to establish a chatroom style talk session.");
        println(" ");
        println("Step 2: Login  via 'talk -login <username>' command. This command");
        println("        logs the user and starts a listener daemon. This has to");
        println("        to be done everytime the peer is restarted.");
        println(" ");
        println("Step 3: User can talk to another user via the command");
        println("        'talk -u <myusername> <destusername>'. This command will prompt the user");
        println("        to enter the message he/she wants to send");
        println(" ");
        println("         JXTA>talk -u moi mike");
        println("         # talk : Connected to user mike");
        println("         Type your message. To exit, type '.' at beginning of line");
        println("  ");
        println("To stop receiving any more talk messages. The user can stop the talk");
        println("listener daemon by entering the command 'talk -logout <username>'");
        println(" ");
        println("OPTIONS");
        println(" ");
        println("    -register register a new user name.");
        println("    -login    log user and set default user.");
        println("    -logout   logout.");
        println("    -search   search for talk users.");
        println("    -u        specify current user name");
        println(" ");
        println("EXAMPLES");
        println(" ");
        println("      JXTA>talk -register me");
        println("      JXTA>talk -login me");
        println("      JXTA>talk -search");
        println("      JXTA>talk -u me you");
        println(" ");
        println("This example shows how a new user 'me'  can register and log into talk,");
        println(" an talk to the user 'you'. User 'you' needs to be registered and logged on.");
        println(" ");
        println("SEE ALSO");
        println(" ");
        println("    xfer sftp mkpipe");
    }
}