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

Store the active sessionList in another class SessionManager.

List socketSessions = new ArrayList<>();

Add incoming session in @OnOpen to list. Remove session from list in @OnClose

@OnClose
public void close(Session session) {
  sessionManager.removeSession(session);
}

To send a message to everyone,

public void broadcast(String message){
    for(Session session: sessionList){
        session.getBasicRemote().sendText(message);
    }
}

You can use the sessionManager.broadcast() method wherever the event triggers.

Here is a complete example of how websocket can be used to make push with HTML5 websocket API. https://metamug.com/article/java-push-notification-with-websocket.php