Package java.util

Interface Observer

public interface Observer

A class can implement the Observer interface when it wants to be informed of changes in observable objects.

Method Summary

Modifier and Type	Method	Description
void	update(Observable o, Object arg)	This method is called whenever the observed object is changed.

Method Detail

update

void update(Observable o,
            @Nullable
            Object arg)

This method is called whenever the observed object is changed. An application calls an Observable object's notifyObservers method to have all the object's observers notified of the change.

Parameters:

o - the observable object.

arg - an argument passed to the notifyObservers method.