code: public int nextNode()
    {
      if (m_foundLast)
        return DTM.NULL;
        
      int next;
  
      m_lastFetched = next = (DTM.NULL == m_lastFetched)
                             ? m_context
                             : DTM.NULL;
  
      // m_lastFetched = next;
      if (DTM.NULL != next)
      {
        m_pos++;
  
        return next;
      }
      else
      {
        m_foundLast = true;
  
        return DTM.NULL;
      }
    }
docs: Returns the next node in the set and advances the position of the
  iterator in the set. After a NodeIterator is created, the first call
  to nextNode() returns the first node in the set.
  
  @return  The next <code>Node</code> in the set being iterated over, or
  <code>null</code> if there are no more members in that set.