import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.value.ObservableValue;

public class Main {
    public static void main(String[] args) {
        IntegerProperty counter = new SimpleIntegerProperty(100);

        // Add a change listener to the counter property
        counter.addListener(Main::changed);

        System.out.println("Before changing the counter value-1");
        counter.set(101);
        System.out.println("After changing the counter value-1");

        System.out.println();
        System.out.println("Before changing the counter value-2");
        counter.set(102);
        System.out.println("After changing the counter value-2");

        // Try setting the same value
        System.out.println();
        System.out.println("Before changing the counter value-3");
        counter.set(102); // No change event will be fired.
        System.out.println("After changing the counter value-3");

        // Try setting a different value
        System.out.println();
        System.out.println("Before changing the counter value-4");
        counter.set(103);
        System.out.println("After changing the counter value-4");
    }

    public static void changed(ObservableValue<? extends Number> prop, 
                               Number oldValue, 
                               Number newValue) {
        System.out.print("Counter changed: ");
        System.out.println("Old = " + oldValue + ", new = " + newValue);
    }
}