设计模式——行为型模式_模板方法模式

1. 类图

2. 代码

• 总抽象类Game——提供模板

  • public abstract class Game {
       abstract void initialize();
       abstract void startPlay();
       abstract void endPlay();
     
       public final void play(){    //模板
          initialize();    //初始化游戏 
          startPlay();    //开始游戏 
          endPlay();    //结束游戏
       }
    }

  • 具体实现类

    • public class Cricket extends Game { 
         @Override
         void endPlay() {
            System.out.println("Cricket Game Finished!");
         } 
         @Override
         void initialize() {
            System.out.println("Cricket Game Initialized! Start playing.");
         } 
         @Override
         void startPlay() {
            System.out.println("Cricket Game Started. Enjoy the game!");
         }
      }
      
      public class Football extends Game { 
         @Override
         void endPlay() {
            System.out.println("Football Game Finished!");
         } 
         @Override
         void initialize() {
            System.out.println("Football Game Initialized! Start playing.");
         } 
         @Override
         void startPlay() {
            System.out.println("Football Game Started. Enjoy the game!");
         }
      }

• 客户端调用

  • public class TemplatePatternDemo {
       public static void main(String[] args) {
     
          Game game = new Cricket();
          game.play();
          System.out.println();
          game = new Football();
          game.play();      
       }
    }

3. 总结

优点：

• 提供了模板，封装不变部分，扩展可变部分
• 代码复用

注：

• 为防止恶意操作，一般模板方法都加上 final 关键词