How do I Send Data to All Threaded Clients in Java

Question

I am fairly new to Java, and I am trying to construct a very basic Java Relay server that sends messages from clients to all connected clients. I have figured out how to do threading to allow multiple connections, but I am having trouble figuring out how to echo an incoming message to ALL connected socket threads.

Here is my Main.java source:

http://pastebin.com/vVewfv3s

Here is my SocketThread.java source:

http://pastebin.com/yHA2BcUi

Basically, I want to know the easiest way with my current coding setup to be able to send an incoming message from one client to all of the other clients. I am currently using the Windows telnet client as the client working with this server.

Answer 1

One trivial way is to keep a collection of clients, say as a map or set. To send a message to all clients, you traverse the linked list of clients and put a reference to the message on each client's send queue. You need to protect these structures with proper inter-thread synchronization, of course.