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