设计模式22-策略模式

1. 概念

     定义一系列的算法，把他们一个个封装起来，并使他们可以互相替换，本模式使得算法可以独立于使用它们的客户。  

2. 案例  

     

package org.demo.strategy.demo01;

abstract class Strategy{
    abstract public void method() ;
}
class StrategyImpl01 extends Strategy{

    @Override
    public void method() {
        System.out.println("算法一");
    }
}

class StrategyImpl02 extends Strategy{

    @Override
    public void method() {
        System.out.println("算法二");
    }
}

class Context{
    private Strategy strategy ;
    public Context(Strategy strategy){
        this.strategy = strategy ;
    }
    
    public void doMethod(){
        strategy.method() ;
    }
}
public class Demo01 {
    public static void main(String[] args) {
        Strategy strategy = new StrategyImpl01() ;
        Context c = new Context(strategy) ;
        c.doMethod() ;
        strategy = new StrategyImpl02() ;
        c = new Context(strategy) ;
         c.doMethod() ;
        
    }
}