SE450: Observer: Cyclic Dependencies [15/28]

Example of a GUI element (a slider) which controls a program variable x.

Program creates Slider.

Slider controls program.

Observer reverse the dependency of Slider on program.

Program can use slider code, but slider decides when to call (back) to the client!

javax.swing.JSlider
javax.swing.event.ChangeListener

java.awt.Button
java.awt.event.ActionListener