Creating custom bindings

If you have a complex logic, you can create your own binding by either extending the corresponding abstract base class—DoubleBinding, StringBinding, ObjectBinding—there are several options for different types; or by using a utility method from the Bindings class. 

Implementing base binding classes

The concept of binding is simple:

• Add a listener to change events you want to track
• Compute the value you want to have

Correspondingly, in the following example, we call bind() for the desired property and override computeValue() method:

    public void start(Stage primaryStage) {
        Button btn = new Button();
        btn.setText("Click me");

        StackPane root = new StackPane();
        root.setBackground(Background.EMPTY);
        root.getChildren().add(btn);

        Scene scene = new Scene(root, 300, 250);

ObjectBinding<Paint> objectBinding = new ObjectBinding<Paint>() {
            {
                bind(btn.pressedProperty()); 
            }
    ...