Scene Graph traversal. Getting all the children of a node recursively

Question

Hi,
Requirement: To resize all the controls of a scene (including controls that contain text like label, button) as per the scene size
Approach: To implement the above requirement (see code snippet below), I added Listeners for width and height properties of a Scene and whenever the scene size changes, I get all the children of the root node of the scene and invoked the setScaleX() and setScaleY() for the children.
Problem: In my design, labels and buttons are wrapped inside VBox, HBox etc. Method getChildrenUnmodifiable() returns only the first level of children and hence my HBox and VBox are getting scaled as per the scene size but not the children of VBox and HBox. Is there a built-in function to get all the children of a node recursively ? Or what is the best way to resize text as the scene size changes ?
Scene mainScene = new Scene(borderPane, PERMANENT_WIDTH,
                PERMANENT_HEIGHT, Color.HONEYDEW);
rootNode = mainScene.getRoot();
        mainScene.widthProperty().addListener(new ChangeListener() {
            @Override
            public void changed(ObservableValue observable, Object oldValue,
                    Object newValue) {
                Double widthScalingFactor = ((Double) newValue) / PERMANENT_WIDTH;
                 ObservableList<Node> children = rootNode.getChildrenUnmodifiable();
                for (Node child : children) {
                    child.setScaleX(widthScalingFactor);
        mainScene.heightProperty().addListener(new ChangeListener() {
            @Override
            public void changed(ObservableValue observable, Object oldValue,
                    Object newValue) {
                Double heightScalingFactor = ((Double) newValue) / PERMANENT_HEIGHT;
                ObservableList<Node> children = rootNode.getChildrenUnmodifiable();
                for (Node child : children) {
                    child.setScaleY(heightScalingFactor);
        });Thanks.

Answer 1

Added the following code to get all the children recursively. now the scaling is applied to all nodes of a scene.
    private static void getChildren(Parent parentNode) {
        if (parentNode.getChildrenUnmodifiable().size() != 0) {
            ObservableList<Node> tempChildren = parentNode
                    .getChildrenUnmodifiable();
            allChildren.addAll(tempChildren);
            for (Node n : tempChildren)
                getChildren((Parent) n);
        } else
            allChildren.add(parentNode);
    }