public DBTCPConnector(Mongo m, ServerAddress addr) throws MongoException {
    _mongo = m;
    _portHolder = new DBPortPool.Holder(m._options);
    _checkAddress(addr);

    _createLogger.info(addr.toString());

    if (addr.isPaired()) {
      _allHosts = new ArrayList<ServerAddress>(addr.explode());
      _createLogger.info("switch to paired mode : " + _allHosts + " -> " + _curAddress);
    } else {
      _set(addr);
      _allHosts = null;
    }
  }
 Node(ServerAddress addr) {
   _addr = addr;
   _port = new DBPort(addr, null, _mongoOptions);
   _names.add(addr.toString());
 }