Java Chat code - from bare basics

Try the following to start the client and server. They will be run in separate threads

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        new JServer().start();
        new JClient().start();
    }

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Something like the following should be OK for the client:

    public void run() {
        try {
            Thread.sleep(1000);
	    Socket s = new Socket("localhost", 1234);
	    Scanner in = new Scanner(s.getInputStream());
	    while(in.hasNext()) {
		System.out.println(in.nextLine());
	    }
	    in.close();
	    s.close();
            System.out.println("JClient run() ");
        } catch (Exception e) {
            System.out.println("run() excep: " + e);
        }
    }

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** Thx all **

With the constructors and accept Thread now lined up and working, what would the code be like for a JFrame that can receive and send chat data? In a dataoutputstream?

Decouple what you have from the gui by sending events containing the chat strings and adding the gui as a listener

Thx All

I have patched together all of your combined suggestions into a "final"  attempt at the JClient and JServer startoff. (attached)

By final, I mean good as a solid starting off point to begin a network chat/game java framework.
It is printf happy right now.
All that needs to be done from here is to design a JFrame interface, game objects or chat interface. and atttach the necessary sockets and streams to each item.
........
Speaking of which,
I am considering scrapping the all text system (for my game) and using a dataoutputstream that sends Structs/Objects/holders that contain all data members possible for any message.
This would include chat items, in game movement, etc.
I doubt it, but is there anything I have overlooked in the attached code? considering I may want to bullet-proof it later.
?
Thanks
JServer4experts2.txt.txt

The main thing you need to go is to get it multi-threaded. You need to handle each incoming connection in a separate thread

Thx,
That is what my framework does, doesnt it?


JClient is a Thread.
I have an array of all the sockets

Once I fill in the run() method, it should all be set up well? Server -> client
?

No - your multithreading so far is there to run the client and server in the same vm - something of course that wouldn't happen in a 'real' C/S application.

The multithreading i'm referring to should exist at the server to allow more than one client to connect. In a single threaded model, a new connection cannot be made until the previous client has been fully serviced

Right..
So, an accept()ed client needs to be passed to a Handler thread of some kind?
one new Handler(socket) for each connection? (a list of Handlers)
so the accept() loop thread carries on? without missing a step.

Something on the lines of?...

private static class Handler extends Thread {
        private String name;
        private Socket socket;
        private BufferedReader in;
        private PrintWriter out;

....
?

>>So, an accept()ed client needs to be passed to a Handler thread of some kind?

Exactly right. Implementing Runnable is more flexible than extending Thread though. You can pass the Socket to the ctor of the handler

I've seen that a bit recently (implementing Runnable). Should I give up on extending Thread, then?
What does "more flexible" mean? Is this maybe related to VM implementation?
Any worst case examples? Different Threads fighting eachother?

It's just a question of convenience. One example would be inheritance: java doesn't support multiple implementation inheritance, only single inheritance, so once you've extended Thread, you've used up your quota

Take a look at the following for a way to create a multi-threaded server. If you use that as your basis, you only need to provide implementations of the Service interface:

http://technojeeves.com/joomla/index.php/free/84-server-by-david-flanagan

CEHJ, I like the Service angle. TY
Very appealing.

With this multi-server, does the server notify every service? or only one (I might make that one service notify the others, but that would be very inefficient) How might I make the Server broadcast input to every attached Service,
assuming I make that Service a chat window / or game client.

There's no broadcast element involved here, since each service is designed to be independent.

I think you should probably look into Java software that's more directly related to chat, e.g. an XMPP server

Great XMPP link,

however, I'm more interested in Java code, maybe 2 classes - A multiserver class and a Client class/interface.
I titled the question with chat code, because I knew if I got code for a multi-server chat, I could message it into what I need for a game server (RTS)
Should I del this question and ask for RTS server code?

I'm going to have another look at the Flanagan code myself later. I can't remember if it's possible to have contextual info in each Service. If that can be done, then it should be quite possible for Service-state info to be retained, which should allow broadcasting and perhaps some coupling

Any luck?

Should be possible. Have a look at the Control class - of necessity it coordinates clients and server so it should be possible to use something like this to coordinate chat clients too

Great code. Thanks

Funny that he's doing exactly what i suggested ;-)