private void populatePostOrder(TreeNode<T> currentNode, final LinkedList<TreeNode<T>> stack) {
List<TreeNode<T>> children = currentNode.getChildren();
for (TreeNode<T> childNode : children) {
populatePostOrder(childNode, stack);
}
stack.addLast(currentNode);
}
public Iterator<TreeNode<T>> getPostOrderIter() {
final LinkedList<TreeNode<T>> stack = new LinkedList<TreeNode<T>>();
populatePostOrder(this, stack);
return stack.iterator();
}