行为型模式-策略模式

package per.mjn.pattern.strategy;

// 抽象策略类
public interface Strategy {

    void show();
}

package per.mjn.pattern.strategy;

// 具体策略类，用来封装算法
public class StrategyA implements Strategy {
    @Override
    public void show() {
        System.out.println("买一送一");
    }
}

package per.mjn.pattern.strategy;

// 具体策略类，用来封装算法
public class StrategyB implements Strategy {
    @Override
    public void show() {
        System.out.println("满200元减50元");
    }
}

package per.mjn.pattern.strategy;

// 具体策略类，用来封装算法
public class StrategyC implements Strategy {
    @Override
    public void show() {
        System.out.println("满1000元加一元换购任意200元以下商品");
    }
}

package per.mjn.pattern.strategy;

// 促销员（环境类）
public class SalesMan {

    // 聚合策略类对象
    private Strategy strategy;

    public SalesMan(Strategy strategy) {
        this.strategy = strategy;
    }

    // 由促销员展示促销活动给用户
    public void salesManShow() {
        strategy.show();
    }
}

package per.mjn.pattern.strategy;

public class Client {
    public static void main(String[] args) {
        // 春节来了，使用春节促销活动
        SalesMan salesMan = new SalesMan(new StrategyA());

        // 展示促销活动
        salesMan.salesManShow();
    }
}