code: public void detach()
    { 
    	m_currentNode = DTM.NULL;
    	m_dtm = null;
    	m_traverser = null;
    	m_isFresh = true;
    	m_root = DTM.NULL;
    }
docs: Detaches the walker from the set which it iterated over, releasing
  any computational resources and placing the iterator in the INVALID
  state.