标签：灵活 bst 代理 out 使用 http pac 实例 decorator
1.定义：在不改变原有对象的基础之上，将功能附加到对象上；
提供了比继承更有弹性的替代方案(扩展原有对象功能)。
2.类型：结构型
3.适用场景：扩展一个类的功能或给一个类添加附加职责；
动态的给一个对象添加功能，这些功能可以再动态的撤销。
4.优点：继承的有力补充，比继承灵活，不改变原有对象的情况下给一个对象扩展功能；
通过使用不同装饰类以及这些装饰类的排列组合，可以实现不同效果；
符合开闭原则。
5.缺点：会出现更多的代码，更多的类，增加程序复杂性；
动态装饰时，多层装饰时会更复杂。
6.相关设计模式：代理模式，适配器模式。
7.实例目录package
8.实例UML类图
9.代码
1 package com.geely.design.pattern.structural.decorator.v1; 2 3 public class Battercake { 4 public String getDesc(){ 5 return "煎饼"; 6 } 7 public int cost(){ 8 return 8; 9 } 10 }
1 package com.geely.design.pattern.structural.decorator.v1; 2 3 public class BattercakeWithEgg extends Battercake { 4 @Override 5 public String getDesc() { 6 return super.getDesc() + " 加一个鸡蛋"; 7 } 8 9 @Override 10 public int cost() { 11 return super.cost() + 1; 12 } 13 }
1 package com.geely.design.pattern.structural.decorator.v1; 2 3 public class BattercakeWithEggSausage extends BattercakeWithEgg { 4 @Override 5 public String getDesc() { 6 return super.getDesc() + "加一根香肠"; 7 } 8 9 @Override 10 public int cost() { 11 return super.cost()+2; 12 } 13 }
1 package com.geely.design.pattern.structural.decorator.v1; 2 3 public class Test { 4 public static void main(String[] args) { 5 Battercake battercake = new Battercake(); 6 System.out.println(battercake.getDesc()+ "销售价格：" + battercake.cost()); 7 8 BattercakeWithEgg battercakeWithEgg = new BattercakeWithEgg(); 9 System.out.println(battercakeWithEgg.getDesc()+ "销售价格：" + battercakeWithEgg.cost()); 10 11 BattercakeWithEggSausage battercakeWithEggSausage = new BattercakeWithEggSausage(); 12 System.out.println(battercakeWithEggSausage.getDesc()+ "销售价格：" + battercakeWithEggSausage.cost()); 13 } 14 }
1 package com.geely.design.pattern.structural.decorator.v2; 2 3 public abstract class ABattercake { 4 public abstract String getDesc(); 5 public abstract int cost(); 6 }
1 package com.geely.design.pattern.structural.decorator.v2; 2 3 public class Battercake extends ABattercake { 4 @Override 5 public String getDesc() { 6 return "煎饼"; 7 } 8 9 @Override 10 public int cost() { 11 return 8; 12 } 13 }
1 package com.geely.design.pattern.structural.decorator.v2; 2 3 public abstract class AbstractDecorator extends ABattercake { 4 private ABattercake aBattercake; 5 6 public AbstractDecorator(ABattercake aBattercake) { 7 this.aBattercake = aBattercake; 8 } 9 10 protected abstract void doSomething(); 11 12 @Override 13 public String getDesc() { 14 return aBattercake.getDesc(); 15 } 16 17 @Override 18 public int cost() { 19 return aBattercake.cost(); 20 } 21 }
1 package com.geely.design.pattern.structural.decorator.v2; 2 3 public class EggDecorator extends AbstractDecorator { 4 public EggDecorator(ABattercake aBattercake) { 5 super(aBattercake); 6 } 7 8 @Override 9 protected void doSomething() { 10 11 } 12 13 @Override 14 public String getDesc() { 15 return super.getDesc()+" 加一个鸡蛋"; 16 } 17 18 @Override 19 public int cost() { 20 return super.cost() + 1; 21 } 22 }
1 package com.geely.design.pattern.structural.decorator.v2; 2 3 public class SausageDecorator extends AbstractDecorator { 4 public SausageDecorator(ABattercake aBattercake) { 5 super(aBattercake); 6 } 7 8 @Override 9 protected void doSomething() { 10 11 } 12 13 @Override 14 public String getDesc() { 15 return super.getDesc()+" 加一根香肠"; 16 } 17 18 @Override 19 public int cost() { 20 return super.cost()+2; 21 } 22 }
1 package com.geely.design.pattern.structural.decorator.v2; 2 3 public class Test { 4 public static void main(String[] args) { 5 ABattercake aBattercake; 6 aBattercake = new Battercake(); 7 aBattercake = new EggDecorator(aBattercake); 8 aBattercake = new EggDecorator(aBattercake); 9 aBattercake = new SausageDecorator(aBattercake); 10 11 System.out.println(aBattercake.getDesc()+ "销售价格：" + aBattercake.cost()); 12 } 13 }
标签：灵活 bst 代理 out 使用 http pac 实例 decorator
原文地址：https://www.cnblogs.com/linbq1911/p/10229060.html
