设计模式-命令模式

  1 package com.pattern.command;
  2 
  3 // 服务员,相当于Invoker
  4 public class Waiter {
  5     private Order order = null;
  6 
  7     public void action() {
  8         getOrder().cook();
  9     }
 10 
 11     // 下单接口
 12     public void setOrder(Order order) {
 13         this.order = order;
 14     }
 15 
 16     public Order getOrder() {
 17         if (order == null) {
 18             order = new EmptyOrder();
 19         }
 20         return order;
 21     }
 22 }
 23 
 24  
 25 
 26 package com.pattern.command;
 27  
 28 // 厨师,相当于Receiver
 29 public class Cooker {
 30     // 具体的执行逻辑,烹饪快餐
 31     public void cookSimpleMeal() {
 32         System.out.println("cook simple meal...");
 33     }
 34 
 35     // 具体的执行逻辑,烹饪招牌菜
 36     public void cookPopularMeal() {
 37         System.out.println("cook popular meal...");
 38     }
 39 }
 40 
 41 
 42 
 43 package com.pattern.command; 
 44 
 45 // 订单接口,相当于Command
 46 public interface Order {
 47     public void cook();
 48 }
 49 
 50 
 51 
 52 package com.pattern.command;
 53 
 54 // 空的订单,用于代表默认订单
 55 public class EmptyOrder implements Order {
 56     @Override
 57     public void cook() {
 58         System.out.println("cooker has no order");
 59     }
 60 }
 61 
 62 
 63 
 64 package com.pattern.command;
 65 
 66 // 快餐订单,相当于ConcreteCommand
 67 public class SimpleOrder implements Order {
 68     public Cooker cooker = null;
 69 
 70     public SimpleOrder(Cooker cooker) {
 71         this.cooker = cooker;
 72     }
 73 
 74     @Override
 75     public void cook() {
 76         cooker.cookSimpleMeal();
 77     }
 78 }
 79 
 80 
 81 
 82 package com.pattern.command;
 83 
 84 // 招牌菜订单,相当于ConcreteCommand
 85 public class PopularOrder implements Order {
 86     public Cooker cooker = null;
 87 
 88     public PopularOrder(Cooker cooker) {
 89         this.cooker = cooker;
 90     }
 91 
 92     @Override
 93     public void cook() {
 94         cooker.cookPopularMeal();
 95     }
 96 }
 97 
 98 
 99 
100 package com.pattern.command;
101  
102 // 订单测试类
103 public class OrderTest {
104     public static void main(String args[]) {
105         // 服务员
106         Waiter waiter = new Waiter();
107         // 厨师
108         Cooker cooker = new Cooker();
109  
110         waiter.action();
111         // 下单(快餐)
112         waiter.setOrder(new SimpleOrder(cooker));
113         waiter.action();
114         // 下单(招牌菜)
115         waiter.setOrder(new PopularOrder(cooker));
116         waiter.action();
117     }
118 }