Calling an open socket server

[Mike Cunningham]

I have a program that calls another java program whose basic purpose is to open a server socket, listen for a response, and then close the server socket.

I would prefer to open the socket for responses once and be able to get a handle on it when needed.

If anyone can inform me of the process for this or throw in a snippit of code to get me started I would really appreciate it.

Thanks,

Mike

[Elihu Smails]

I am not sure what you mean by "I have a program that calls another java program" Are you talking about one Java class that calls another java class?

You should just open a ServerSocket, and have the ServerSocket.accept pass the returning Socket off to logic that will handle the connection.

[Mike Cunningham]

Yes, it's a java program calling another java program. I use the ServerSocket.accept() method to get a handle on the server socket. The part that I'm unclear about is how to

pass the returning Socket off to logic that will handle the connection

for the multiple sessions that take place in this application.

[David Harkness]

ServerSocket.accept() returns a new Socket with I/O streams for the connected client. Since you want to handle multiple simultaneous clients (do you?), you can't handle I/O with the client right there in that thread.

Instead, you create a new Thread (or grab one from a ThreadPool) and give it the Socket to handle client I/O.

Then you continue in your accept loop, calling ServerSocket.accept() for the next client connection.

The easiest way is to have one Thread for the accept loop and one Thread per client connection. The class that will handle client I/O could look something like this:

public class ClientHandler implements Runnable
{
    private Socket conn;
 
    public ClientHandler ( Socket conn ) {
        this.conn = conn;
    }
 
    public void run ( ) {
        // use "conn" to talk to client
        ...
        conn.close();
    }
}

Your server's accept loop would be like this:

while ( ! done ) {
    Socket conn = ServerSocket.accept();
    new Thread(new ClientHandler(conn)).start();
}

Obviously, you'll need to fill those out a bit.