code: protected int getNextNode()
    {
      m_lastFetched = (DTM.NULL == m_lastFetched)
                       ? m_traverser.first(m_context)
                       : m_traverser.next(m_context, m_lastFetched);
      return m_lastFetched;
    }
docs: Get the next node via getFirstAttribute && getNextAttribute.