773: Mainline

Observers are instances of a class that implements the Observer interface defined in the java.util package. That interface requires the class to define an update method, which is called whenever the observer is activated by a connected model.

In the following preview of an embedded update definition, the update method fetches a rating and title from a movie and uses that rating and title to set the value and title displayed by a meter. The arguments happen to be ignored:

public void update (Observable observable, Object object) { 
 getMeter().setValue(getMovie().rating()); 
 getMeter().setTitle(getMovie().getTitle());                     
}