用JAVA SOCKET制作一个广播信使的程序

用JAVA SOCKET制作一个广播信使的程序(7)    window.getContentPane().add (output,BorderLayout.CENTER);
    //TO ADD TextArea (output) AT THE CENTER OF THE WINDOW
   window.getContentPane().add (input,BorderLayout.SOUTH);
    //TO ADD THE Textbox (input) AT THE BOTTOM (SOUTH)

protected DataInputStream dataIn;
protected DataOutputStream dataOut;
protected Thread listener;

public synchronized void start () throws IOException {
    //THREAD SYNCHRONIZATION METHOD FOR STARTING BROADCAST
   if (listener == null) {
      Socket socket = new Socket (host, port);    //TO INITIALIZE
                                                  //THE SOCKET
   try {
      dataIn = new DataInputStream
         (new BufferedInputStream (socket.getInputStream ()));
      dataOut = new DataOutputStream
         (new BufferedOutputStream (socket.getOutputStream ()));
         dataOut.writeUTF (yourname+" has loggged on\n ");
         }
catch (IOException ex)
   {
      socket.close ();
      throw ex;
   }
}
   listener = new Thread (this);
   listener.start ();
   window.setVisible (true);
   }
}
public synchronized void stop () throws IOException
    //THREAD SYNCHRONIZATION METHOD FOR STOPPING THE BROADCAST