Question

I am engaging the following problems:

1. I need to write a server program, will accept multiple clients
2. all clients are subscribing the same data from server, for example the stock price update.
3. each clients can send simple commands to server like “logon”, “stop”

So here is my solution, Since I am not very experianced in multithread/tcp, I want to know is it a good solution? if not, is there any better solution? is it necessary to have a thread for each client socket? Thanks
BTW: sorry for confusing every one, it is a small project that only involve 5-10 classes.

class AcceptThread {
    ......
    public void run () {
        ControlThread controlThread = new ControlThread();
        controlThread.start();

        Socket socket = new Socket(port);
        while (!stop) {
            Socket s = socket.accept();
            controlThread.addClient (s);
        }
    }
}

class ControlThread {
    Set<Scoket> clients;
    SendDataThread sendDataThread;  

    public ControlThread () {
        sendDataThread = new SendDataThread();
        sendDataThread.start();     
    }

    public void addClient (Socket socket) {
        clients.add(socket);
        sendDataThread.addListener(socket);
    }

    public void run () {
        ......
        for (Socket s : clients) {
            if (s.getInputStream().available()) {
                //read command from s
            }
        }
        ......              
    }
}

class SendDataThread () {
    Set<Scoket> listeners;

    public void addListener (Socket s) {
        listeners.add(s);
    }

    public void run () {
        for (Socket s: listeners) {
            // send data to each listener
        }
    }
}

Answer 1

is it necessary to have a thread for each client socket?

No, as a matter of fact, I wouldn’t even not recommend it. If it’s a small project and you don’t want to use any existing library, I would suggest you use the java.nio package and the SelectableChannels. With a so called selector you can easily monitor clients for incoming data in a non-blocking way.

Here are a few useful links:

• NIO Examples (from the official tutorial)
• The Rox Java NIO Tutorial