44 lines
922 B
Java
44 lines
922 B
Java
// polymorphism/Transmogrify.java
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// (c)2020 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// Dynamically changing the behavior of an object
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// via composition (the "State" design pattern)
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class Actor {
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public void act() {}
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}
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class HappyActor extends Actor {
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@Override
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public void act() {
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System.out.println("HappyActor");
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}
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}
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class SadActor extends Actor {
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@Override
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public void act() {
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System.out.println("SadActor");
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}
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}
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class Stage {
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private Actor actor = new HappyActor();
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public void change() { actor = new SadActor(); }
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public void performPlay() { actor.act(); }
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}
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public class Transmogrify {
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public static void main(String[] args) {
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Stage stage = new Stage();
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stage.performPlay();
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stage.change();
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stage.performPlay();
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}
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}
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/* Output:
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HappyActor
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SadActor
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*/
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