Find websocket session by id in Java EE 7

Question

I've read Java EE documentation and for me is unclear one thing. According to API, the only way to find another Session is a code like this: (assuming that we've identifier of other session):

import javax.websocket.Session;
...
private static Session findOtherSessionById(Session user, String id) {
    for (Session session : user.getOpenSessions()) {
        if (id.equals(session.getId())) {
            return session;
        }
    }
    return null;
}

But when we've thousands of users, this code is a performance bottleneck.

So, is there a way to get Session by id fast without using own ConcurrentHashMap for this? Or maybe some application server has undocummented feature for this (for me Wildfly would be great)?

Answer 1

You can do something like:

Map<String, Session> map = new HashMap<>();
static Map<String, Session> peers = Collections.synchronizedMap(map);

@OnOpen
public void onOpen(Session session) {
   peers.add(session.getId(), session);
}

@OnClose
public void onClose(Session session) {
    peers.remove(session.getId());
}

private static Session findOtherSessionById(Session user, String id) {
    if (peers.containsKey(user.getId()) {
        return peers.get(user.getId());
    }
}