public int getNumConnectedClients(String managerName) {
        Map<StreamID, LocalClientSession> clients = sessionsByManager.get(managerName);
        if (clients == null) {
            return 0;
        }
        else {
            return clients.size();
        }
    }
Returns the number of connected clients to a specific connection manager.

@param managerName the name of the connection manager.
@return the number of connected clients to a specific connection manager.
xmppserver/src/main/java/org/jivesoftware/openfire/multiplex/ConnectionMultiplexerManager.java