code: public boolean contains(Node node) {
      if (node == null) return false;
      netlock.readLock().lock();
      try {
        Node parent = node.getParent();
        for(int level=node.getLevel(); parent!=null&&level>0;
            parent=parent.getParent(), level--) {
          if (parent == clusterMap)
            return true;
        }
      } finally {
        netlock.readLock().unlock();
      }
      return false; 
    }
docs: Check if the tree contains node <i>node</i>
  
  @param node
  a node
  @return true if <i>node</i> is already in the tree; false otherwise