code: public long getPosition()
     {
        initialize();
        long position = scoreNodes.getPosition() - invalid;
        // scoreNode.getPosition() is one ahead
        // if there is a prefetched node
        if (next != null)
        {
           position--;
        }
        return position;
     }
docs: Returns the current position in this <code>NodeIterator</code>.
  @return the current position in this <code>NodeIterator</code>.