How to implement push to client using Java EE 7 WebSockets?

Question

I\'ve browsed a lot of Web Socket examples, presentation slides and they are mostly concentrated on a rather simple scenarios in which client-server communication is initiat

Answer 1

Probably this is not most elegant way but just to demonstrate idea. Method broadcast() will send message to all connected clients.

@ServerEndpoint("/echo")
public class ServerEndPoint {

    private static Set userSessions = Collections.newSetFromMap(new ConcurrentHashMap());

    @OnOpen
    public void onOpen(Session userSession) {
        userSessions.add(userSession);
    }

    @OnClose
    public void onClose(Session userSession) {
        userSessions.remove(userSession);
    }

    @OnMessage
    public void onMessage(String message, Session userSession) {
        broadcast(message);
    }

    public static void broadcast(String msg) {
        for (Session session : userSessions) {
            session.getAsyncRemote().sendText(msg);
        }
    }

}