private ZooKeeper getZooKeeper() {
    ZooKeeper zk = zooKeeper.get();
    Preconditions.checkArgument(zk != null, "Not connected to zooKeeper.");
    return zk;
  }
private ZooKeeper getZooKeeper ( ) { ZooKeeper zk = zooKeeper . get ( ) ; Preconditions . checkArgument ( zk != null , "Not connected to zooKeeper." ) ; return zk ; }
@return Current {@link ZooKeeper} client.