35 lines
745 B
Java
35 lines
745 B
Java
|
//: polymorphism/Transmogrify.java
|
||
|
|
// Dynamically changing the behavior of an object
|
||
|
|
// via composition (the "State" design pattern).
|
||
|
|
import static net.mindview.util.Print.*;
|
||
|
|
|
||
|
|
class Actor {
|
||
|
|
public void act() {}
|
||
|
|
}
|
||
|
|
|
||
|
|
class HappyActor extends Actor {
|
||
|
|
public void act() { print("HappyActor"); }
|
||
|
|
}
|
||
|
|
|
||
|
|
class SadActor extends Actor {
|
||
|
|
public void act() { print("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();
|
||
|
|
}
|
||
|
|
} /* Output:
|
||
|
|
HappyActor
|
||
|
|
SadActor
|
||
|
|
*///:~
|