/**
   * Set the root node of the TreeWalker.
   *
   * @param root non-null reference to the root, or starting point of the query.
   */
  public void setRoot(int root) {

    super.setRoot(root);

    m_exprObj =
        FilterExprIteratorSimple.executeFilterExpr(
            root,
            m_lpi.getXPathContext(),
            m_lpi.getPrefixResolver(),
            m_lpi.getIsTopLevel(),
            m_lpi.m_stackFrame,
            m_expr);
  }
 /**
  * Set the root node of the TreeWalker. (Not part of the DOM2 TreeWalker interface).
  *
  * @param root The context node of this step.
  */
 public void setRoot(int root) {
   super.setRoot(root);
   m_iterator = getDTM(root).getAxisIterator(m_axis);
   m_iterator.setStartNode(root);
 }