f.java

import javafx.beans.InvalidationListener;
import javafx.beans.binding.*;
import javafx.beans.property.FloatProperty;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleFloatProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.value.ChangeListener;

public class Example02 {
    private static IntegerProperty ip = new SimpleIntegerProperty(-100);

    public static void main(String[] args) {
        createProperty();
        testChangeListeners();
        testBinding();
        testBiDirectionalBinding();
        testCalculatedValueBinding();
    }

    private static void createProperty() {
        ip = new SimpleIntegerProperty(301);
    }

    public static void testChangeListeners() {
        ChangeListener listener = (observable, oldValue, newValue) ->
                System.out.printf("Value changed, old_value = %s, new_value = %s\n", oldValue, newValue);

        ip.addListener(listener);
        ip.set(100);
        ip.removeListener(listener);
    }

    public static void testBinding() {
        IntegerProperty anotherIp = new SimpleIntegerProperty(0);

        anotherIp.bind(ip);

        ip.set(500);
        System.out.printf("ip.get() = %s\n", ip.get());
        anotherIp.unbind();
    }

    private static void testBiDirectionalBinding() {
        IntegerProperty anotherIp = new SimpleIntegerProperty(0);

        anotherIp.bindBidirectional(ip);

        ip.setValue(100);
        anotherIp.setValue(200);
        ip.unbindBidirectional(anotherIp);
    }

    public static void testCalculatedValueBinding() {
        FloatProperty width = new SimpleFloatProperty(10.0f);
        FloatProperty height = new SimpleFloatProperty(20.0f);
        FloatProperty radius = new SimpleFloatProperty(1.5f);

        FloatBinding rectArea = new FloatBinding() {
            // unnamed constructor
            {
                // binding this binding to the width and height properties
                // i.e. if either one changes, computeValue will be called
                super.bind(width, height);
            }

            @Override
            protected float computeValue() {
                return width.get() * height.get();
            }
        };

        rectArea.addListener((observable, oldValue, newValue) -> {
            System.out.println(">> Rectangle area changed to " + newValue.intValue());
        });

        // create a binding using the Fluent API, areaCircle = PI * radius * radius
        NumberBinding areaCircle = radius.multiply(radius).multiply(Math.PI);
        areaCircle.addListener((observable, oldValue, newValue) -> {
            System.out.println(">> Circle area changed to " + newValue.intValue());
        });

        // create a binding that adds multiple things together
        NumberBinding total = width.add(height).add(radius);

        total.addListener((observable1, oldValue1, newValue) -> {
            System.out.println(">> Total changed to " + newValue.intValue());
        });

        // can create bindings with other types too
        StringBinding message = (StringBinding) Bindings
                .concat("Circle area = ")
                .concat(areaCircle)
                .concat(", Rectangle area = ")
                .concat(rectArea);

        message.addListener((observable, oldValue, newValue) -> {
            System.out.printf(">> Message changed to '%s'\n", newValue);
        });

        // can use simple logic using the Fluent API as well
        StringBinding largerMessage = (StringBinding) Bindings
                .when(rectArea.greaterThan(areaCircle))
                .then(Bindings.concat("Larger area is rectangle = ").concat(rectArea))
                .otherwise(Bindings.concat("Larger area is circle = ").concat(areaCircle));

        largerMessage.addListener((observable, oldValue, newValue) -> {
            System.out.printf(">> Larger message changed to '%s'\n", newValue);
        });

        // display the area
        System.out.println("Displaying current values...");
        System.out.printf("width.get() = %s\n", width.get());
        System.out.printf("height.get() = %s\n", height.get());
        System.out.printf("rectArea.get() = %s\n", rectArea.get());
        System.out.printf("circleArea.getValue() = %s\n", areaCircle.getValue());
        System.out.printf("total.getValue() = %s\n", total.getValue());
        System.out.printf("message.getValue() = '%s'\n", message.getValue());
        System.out.printf("largerMessage.getValue() = '%s'\n", largerMessage.getValue());
        System.out.println();

        // change property values
        System.out.println("Changing property values...");
        width.set(25.0f);
        height.set(17.25f);
        radius.set(12.45f);

        System.out.println();
        System.out.println("Displaying current values...");
        System.out.printf("width.get() = %s\n", width.get());
        System.out.printf("height.get() = %s\n", height.get());
        System.out.printf("rectArea.get() = %s\n", rectArea.get());
        System.out.printf("circleArea.getValue() = %s\n", areaCircle.getValue());
        System.out.printf("total.getValue() = %s\n", total.getValue());
        System.out.printf("message.getValue() = '%s'\n", message.getValue());
        System.out.printf("largerMessage.getValue() = '%s'\n", largerMessage.getValue());
    }

}