How to trigger property invalidation?

Richard Bair richard.bair at
Fri Nov 2 09:30:49 PDT 2012

In Region we have a custom property that we can use to force invalidation. Is this sort of what you're looking for?

    private InsetsProperty insets = new InsetsProperty();
    public final Insets getInsets() { return insets.get(); }
    public final ReadOnlyObjectProperty<Insets> insetsProperty() { return insets; }
    private final class InsetsProperty extends ReadOnlyObjectProperty<Insets> {
        private Insets cache = null;
        private ExpressionHelper<Insets> helper = null;

        @Override public Object getBean() { return Region.this; }
        @Override public String getName() { return "insets"; }

        @Override public void addListener(InvalidationListener listener) {
            helper = ExpressionHelper.addListener(helper, this, listener);

        @Override public void removeListener(InvalidationListener listener) {
            helper = ExpressionHelper.removeListener(helper, listener);

        @Override public void addListener(ChangeListener<? super Insets> listener) {
            helper = ExpressionHelper.addListener(helper, this, listener);

        @Override public void removeListener(ChangeListener<? super Insets> listener) {
            helper = ExpressionHelper.removeListener(helper, listener);

        void fireValueChanged() {
            cache = null;

        @Override public Insets get() {
            // If a shape is specified, then we don't really care whether there are any borders
            // specified, since borders of shapes do not contribute to the insets.
            if (_shape != null) return getPadding();

            // If there is no border or the border has no insets itself, then the only thing
            // affecting the insets is the padding, so we can just return it directly.
            final Border b = getBorder();
            if (b == null || Insets.EMPTY.equals(b.getInsets())) {
                return getPadding();

            // There is a border with some non-zero insets and we do not have a _shape, so we need
            // to take the border's insets into account
            if (cache == null) {
                // Combine the padding and the border insets.
                // TODO note that negative border insets were being ignored, but
                // I'm not sure that that made sense or was reasonable, so I have
                // changed it so that we just do simple math.
                // TODO Stroke borders should NOT contribute to the insets. Ensure via tests.
                final Insets borderInsets = b.getInsets();
                final Insets paddingInsets = getPadding();
                cache = new Insets(
                        borderInsets.getTop() + paddingInsets.getTop(),
                        borderInsets.getRight() + paddingInsets.getRight(),
                        borderInsets.getBottom() + paddingInsets.getBottom(),
                        borderInsets.getLeft() + paddingInsets.getLeft()
            return cache;

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