Help: Send and Receive through Datagram Socket

Question

I am trying to create a client/server using Datagram Socket (UDP) as communication. I have a Recive and a Send class that implements runnable and are responsible for receiving and sending of message. I have two other classes Server and Client that are utilizing these. Now i can get the receive and send to work fine, but i am having trouble retrieving the message from the receive thread that i created in each of server/client. I've tried inserting a method so the server/client can call on to get the message (Receive.Get_Message()) but unfortunately this isn't working as i wanted. Since my server and clients are not implemented as runnables, i can only issue the command in some serialize fashion. What i really want to do is that whenever the message is receive by the Receive thread, it will immediately be send back to server/client and display right then, independent of what i was doing. (i have a command interface for S/C so it just sits there to wait for command, now what i would like is to have the S/C display the message it gets immediately after it gets it even when it's waiting for user input. since my program is waiting for a command, i really could not use the method describe above to achieve this) Could anyone help me with this?
Thanks!
Hung-Hsun Su

Answer 1

u cant use the observer pattern. or at least i can't figure out how to implement it with sockets.
you should use threading.
public void run()
  while(true)
     //keep reading from socket
     InStream output = socket.getInputStream();
     InputStreamReader ir = new InputStreamReader(output)
     BufferedReader reader = new BufferedReader(ir);
     String s = null;
     while(s == null)
       s = reader.readLine();
     //then do whatever you want to the received string "s"
}