public NodeIterator getNthDescendant(int node, int n) { return _domImpl.getNthDescendant(node, n);
public NodeIterator getNthDescendant(int type, int n) { return _domImpl.getNthDescendant(_reverse[type], n);
    public NodeIterator getNthDescendant(int node, int n) {	return _domImpl.getNthDescendant(node, n);    }