23种设计模式之——策略者设计模式

package com.vlctech.dao;

/**
* 首先定义一个策略接口
* @author 金佳杰
*
*/
public interface IStrategy {
//每个策略都是一个可执行算法
public void operate();
}

package com.vlctech.dao.impl;

import com.vlctech.dao.IStrategy;

/**
* 策略一
* @author 金佳杰
*/
public class FirstStrategy implements IStrategy {
@Override
public void operate() {
// TODO Auto-generated method stub
System.out.println("策略者一");
}
}

package com.vlctech.dao.impl;

import com.vlctech.dao.IStrategy;

/**
* 策略二
* @author 金佳杰
*/
public class SecondStrategy implements IStrategy {
@Override
public void operate() {
// TODO Auto-generated method stub
System.out.println("策略者二");
}
}

package com.vlctech.dao.impl;

import com.vlctech.dao.IStrategy;

/**
* 策略三
* @author 金佳杰
*/
public class ThirdlyStrategy implements IStrategy {
@Override
public void operate() {
// TODO Auto-generated method stub
System.out.println("策略者三");
}
}

package com.vlctech.main;

import com.vlctech.dao.IStrategy;

/**
* 策略的统一入口
* @author 金佳杰
*
*/
public class Context {
//定义策略接口
private IStrategy strategy;
//构造方法确定调用那种策略
public Context(IStrategy istrategy){
this.strategy = istrategy;
}

public void operate() {
//调用策略方法
this.strategy.operate();
}
}

package com.vlctech.main;

import com.vlctech.dao.impl.FirstStrategy;
import com.vlctech.dao.impl.SecondStrategy;
import com.vlctech.dao.impl.ThirdlyStrategy;

public class Strategy {
public static void main(String[] args) {
//根据不同的策略对象执行对应的策略方法
Context context;
context = new Context(new FirstStrategy());
context.operate();

context = new Context(new SecondStrategy());
context.operate();

context = new Context(new ThirdlyStrategy());
context.operate();
}
}