Bidirectional binding and StringConverter issue

Question

Hi,
I'm bound a TextField to a DoubleProperty value using a StringConverter. If there is a non parseable value in the textfield, my StringConverter catches the NumberFormatException and returns a valid double value (0.). But in this case the DoubleProperty doesn't become invalid and the textfield text is not updated. I don't have any clue why?
I added a code fragment below. If anybody have an idea, thank you in advance.
JavaFX 2.2 JRE7_25
Code:
@Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("-.-");
        DoubleProperty longvar = new SimpleDoubleProperty(42.0);
        TextField tfInput = new TextField();
        tfInput.textProperty().bindBidirectional(longvar, getDoubleToStringConverter() );
        longvar.addListener(new InvalidationListener() {
            @Override
            public void invalidated(Observable arg0) {
                System.out.println("invalid");
        VBox root = new VBox();
        root.getChildren().add(tfInput);
        primaryStage.setScene(new Scene(root, 300, 250));
        primaryStage.show();
    private StringConverter<Number> getDoubleToStringConverter(){
        return new StringConverter<Number>(){
            @Override
            public String toString(Number t){
                return t.toString();
            @Override
            public Number fromString(String string){
                string = string.replace(",", ".");
                Number tmp = 0.;
                try{
                 tmp = Double.parseDouble(string);
                }catch(NumberFormatException e){
                    tmp = 0.;
                return tmp;

Answer 1

This works as expected for me: I see the text "invalid" any time a change occurs to the text in the text field that causes the value of the DoubleProperty to change.
E.g.:
Select the default value (42.0); press a non-numeric key to change the text. The invalidation listener is invoked.
Delete the text. The invalidation listener is not invoked (the text is now "", which causes a NumberFormatException, the double property is "set" to zero, which is no change so there is no notification).
Enter 0. There is no notification (the value of the DoubleProperty has not changed).
Enter a non-zero numeric value. The invalidation listener is notified.
Change to zero. The invalidation listener is notified
Change to non-numeric text. The invalidation listener is not notified (the value of the DoubleProperty has not changed).
If you're expecting the text to update to zero when non-numeric text is input: I guess the implementation is something like
if (! converter.fromString(text).equals(value)) {
     // updateText
in the binding's method that listens for changes in the DoubleProperty. This is similar to not seeing "1.0" appear in the text field when you type "1"; or "123.0" appearing when you type "0123", etc.