code: void reset(
      Object        key)
    {
      _nodeKey[0] = key;
      _nodeKey[midPoint()] = key;
      _population = 1;
      _rightChild = null;
      _leftChild = null;
      _balance = 0;
    }
docs: Return the node to its post-construction state.
  
  @param key The key that would have been passed in to the constructor
  for the newly allocated node.