public void jjtAddChild(Node n, int i) {
    if (children == null) {
      children = new Node[i + 1];
    } else if (i >= children.length) {
      Node c[] = new Node[i + 1];
      System.arraycopy(children, 0, c, 0, children.length);
      children = c;
    }
    children[i] = n;
  }