Think in Patterns 中的 Decorator模式

package com.lyklinse;/** * <p>Title: </p> * * <p>Description: </p> * * <p>Copyright: Copyright (c) 2009</p> * * <p>Company: </p> * * @author not attributable * @version 1.0 */public class DecoratorPatterns { public DecoratorPatterns() { } public static void main(String[] args) { DecoratorPatterns decoratorpatterns = new DecoratorPatterns(); CoffeeShop2 coffee = new CoffeeShop2(); coffee.testCappuccino(); coffee.testCafeMocha(); }}interface DrinkComponent { String getDescription(); float getTotalCost();}class Mug implements DrinkComponent { public String getDescription() { return "mug"; } public float getTotalCost() { return 0; }}abstract class Decorator implements DrinkComponent { protected DrinkComponent component; Decorator(DrinkComponent component) { this.component = component; } public float getTotalCost() { return component.getTotalCost(); } public abstract String getDescription();}class Espresso extends Decorator { private float cost = 0.75f; private String description = " espresso"; public Espresso(DrinkComponent component) { super(component); } public float getTotalCost() { return component.getTotalCost() + cost; } public String getDescription() { return component.getDescription() + description; }}class Decaf extends Decorator { private String description = " decaf"; public Decaf(DrinkComponent component) { super(component); } public String getDescription() { return component.getDescription() + description; }}class FoamedMilk extends Decorator { private float cost = 0.25f; private String description = " foamed milk"; public FoamedMilk(DrinkComponent component) { super(component); } public float getTotalCost() { return component.getTotalCost() + cost; } public String getDescription() { return component.getDescription() + description; }}class SteamedMilk extends Decorator { private float cost = 0.25f; private String description = " steamed milk"; public SteamedMilk(DrinkComponent component) { super(component); } public float getTotalCost() { return component.getTotalCost() + cost; } public String getDescription() { return component.getDescription() + description; }}class Whipped extends Decorator { private float cost = 0.25f; private String description = " whipped cream"; public Whipped(DrinkComponent component) { super(component); } public float getTotalCost() { return component.getTotalCost() + cost; } public String getDescription() { return component.getDescription() + description; }}class Chocolate extends Decorator { private float cost = 0.25f; private String description = " chocolate"; public Chocolate(DrinkComponent component) { super(component); } public float getTotalCost() { return component.getTotalCost() + cost; } public String getDescription() { return component.getDescription() + description; }}class CoffeeShop2 { public void testCappuccino() { // This just makes sure it will complete // without throwing an exception. // Create a plain cappucino DrinkComponent cappuccino = new Espresso(new FoamedMilk(new Mug())); System.out.println(cappuccino. getDescription().trim() + ": $" + cappuccino.getTotalCost()); } public void testCafeMocha() { // This just makes sure it will complete // without throwing an exception. // Create a decaf cafe mocha with whipped // cream DrinkComponent cafeMocha = new Espresso( new SteamedMilk(new Chocolate(new Whipped( new Decaf(new Mug()))))); System.out.println(cafeMocha.getDescription(). trim() + ": $" + cafeMocha.getTotalCost()); }}