Liu Bei is going to Jiangdong to marry his wife. Before leaving, Zhuge Liang gave Zhao Yun (the best man) three tricks in his bag, saying that he solved the difficult problem according to the secret. Hey, let alone, it
really solved the big problem. In the end, Zhou Yu accompanied his wife Let’s break down again, let’s see what this scene looks like first
. Let me talk about the elements in this scene first: three tricks, one kit, and one Zhao Yun. The trick was given by Comrade Xiao Liang, and the trick was
placed in the kit.
Take out clever tricks from the bag, execute them, and win.
How to express this with a JAVA program? Let's look at the class diagram first:
the three tricks are the same type of stuff, so let's write an interface:
package com.cbf4life.strategy;
/**
* 首先定一个策略接口，这是诸葛亮老人家给赵云的三个锦囊妙计的接口
*
*/
public interface IStrategy {
//每个锦囊妙计都是一个可执行的算法
public void operate();
}
然后再写三个实现类，有三个妙计嘛：
package com.cbf4life.strategy;
/**
* 找乔国老帮忙，使孙权不能杀刘备
*/
public class BackDoor implements IStrategy {
public void operate() {
System.out.println("找乔国老帮忙，让吴国太给孙权施加压力");
}
}
package com.cbf4life.strategy;
/**
* 求吴国太开个绿灯
*/
public class GivenGreenLight implements IStrategy {
public void operate() {
System.out.println("求吴国太开个绿灯,放行！");
}
}
package com.cbf4life.strategy;
/**
* 孙夫人断后，挡住追兵
*/
public class BlockEnemy implements IStrategy {
public void operate() {
System.out.println("孙夫人断后，挡住追兵");
}
}
Well, let’s take a look, there are three tricks, so there needs to be a place to put these tricks, a bag of tricks:
package com.cbf4life.strategy;
/**
* 计谋有了，那还要有锦囊
*/
public class Context {
//构造函数，你要使用那个妙计
private IStrategy straegy;
public Context(IStrategy strategy){
this.straegy = strategy;
}
//使用计谋了，看我出招了
public void operate(){
this.straegy.operate();
}
}
Then it was Zhao Yun who was arrogantly carrying three kits, and pulled Mr.
Liu . Hey, let alone, Xiao Liang's The three tricks are really good, take a look:
package com.cbf4life.strategy;
public class ZhaoYun {
/**
* 赵云出场了，他根据诸葛亮给他的交代，依次拆开妙计
*/
public static void main(String[] args) {
Context context;
//刚刚到吴国的时候拆第一个
System.out.println("-----------刚刚到吴国的时候拆第一个-------------");
context = new Context(new BackDoor()); //拿到妙计
context.operate(); //拆开执行
System.out.println("\n\n\n\n\n\n\n\n");
//刘备乐不思蜀了，拆第二个了
System.out.println("-----------刘备乐不思蜀了，拆第二个了-------------");
context = new Context(new GivenGreenLight());
context.operate(); //执行了第二个锦囊了
System.out.println("\n\n\n\n\n\n\n\n");
//孙权的小兵追了，咋办？拆第三个
System.out.println("-----------孙权的小兵追了，咋办？拆第三个
-------------");
context = new Context(new BlockEnemy());
context.operate(); //孙夫人退兵
System.out.println("\n\n\n\n\n\n\n\n");
/*
*问题来了：赵云实际不知道是那个策略呀，他只知道拆第一个锦囊，
*而不知道是BackDoor这个妙计，咋办？ 似乎这个策略模式已经把计谋名称写出来了
*
* 错！BackDoor、GivenGreenLight、BlockEnemy只是一个代码，你写成first、second、
third，没人会说你错!
*
* 策略模式的好处就是：体现了高内聚低耦合的特性呀，缺点嘛，这个那个，我回去再查查
*/
}
}
This essay is either written by myself or reproduced on the Internet. For personal collection and memo only.