code: public Node nextNode() throws DOMException
      {
        if(!valid)
          throw new DTMDOMException(DOMException.INVALID_STATE_ERR);
        
        int handle=dtm_iter.nextNode();
        if (handle==DTM.NULL)
          return null;
        return dtm_iter.getDTM(handle).getNode(handle);
      }
docs: @return the next node in the set and advance the position of the
  iterator in the set.
  
  @throws DOMException - INVALID_STATE_ERR Raised if this method is
  called after the detach method was invoked.