code: boolean queryLineConnector(int vertex, Line line) {
  		int next = getNextVertex(vertex);
  		if (next == -1)
  			return false;
  
  		if (!m_b_has_attributes) {
  			Point2D pt = new Point2D();
  			getXY(vertex, pt);
  			line.setStartXY(pt);
  			getXY(next, pt);
  			line.setEndXY(pt);
  		} else {
  			Point pt = new Point();
  			queryPoint(vertex, pt);
  			line.setStart(pt);
  			queryPoint(next, pt);
  			line.setEnd(pt);
  		}
  
  		return true;
  	}
docs: Can be used together with get_segment.