int size()
    {
        final int result = ROOM_CACHE.size();
        Log.trace("Room count for service '{}': {}", serviceName, result);
        return result;
    }
Returns the number of chat rooms that are currently actively loaded in memory.

@return a chat room count.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/spi/LocalMUCRoomManager.java