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// : c07:Transmogrify.java
// Dynamically changing the behavior of an object via composition (the State design pattern).
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
abstract class Actor {
public abstract void act();
}
class HappyActor extends Actor {
public void act() {
System.out.println("HappyActor");
}
}
class SadActor extends Actor {
public void act() {
System.out.println("SadActor");
}
}
class Stage {
private Actor actor = new HappyActor();
public void change() {
actor = new SadActor();
}
public void performPlay() {
actor.act();
}
}
public class Transmogrify {
public static void main(String[] args) {
Stage stage = new Stage();
stage.performPlay();
stage.change();
stage.performPlay();
}
} ///:~
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