设计模式-策略模式

1.所用到的类

一个抽象类：用于派生子类
一个Context类：用于变成各种子类形态
N个子类：

2.实现代码

抽象类

public abstract class CashSuper {
    public abstract double acceptCash(double money);
}

Context类

public class CashContext {
    private CashSuper cs;
    public CashContext(String type)
    {
        switch ( type)
            {
                case "正常收费":
                    cs = new CashNormal();
                    break;
                case "满减收费":
                    cs = new CashReturn(300,100);
                    break;
                case "打折收费":
                    cs = new CashRebate(0.8);
                    break;
            }
    }
    public double getResult(double money)
    {
        return cs.acceptCash(money);
    }
}

子类1

public class CashNormal extends CashSuper {
    @Override
    public double acceptCash(double money) {
        return money;
    }
}

子类2

public class CashRebate extends CashSuper {
    private double moneyCondition = 0.0d;
    public CashRebate(double moneyCondition)
    {
        this.moneyCondition = moneyCondition;
    }
    @Override
    public double acceptCash(double money) {
        return money*moneyCondition;
    }
}

子类3

public class CashReturn extends CashSuper {
    private double moneyCondition = 0.0d;
    private double moneyReturn = 0.0d;
    public CashReturn(double moneyCondition,double moneyReturn){
        this.moneyCondition = moneyCondition;
        this.moneyReturn = moneyReturn;
    }
    @Override
    public double acceptCash(double money) {
        if (money >= moneyCondition)
            return money - Math.floor(money / moneyCondition) * moneyReturn;
        return money;
    }
}

调用类

@SpringBootApplication
public class StrategyApplication {
    public static void main(String[] args) {

        double money = 0;
        money = money + new CashContext("正常收费").getResult(500);
        money = money + new CashContext("满减收费").getResult(500);
        money = money + new CashContext("打折收费").getResult(500);
        System.out.println( money);
    }
}

3.总结

工厂是创建型模式,它的作用就是创建对象; 策略是行为型模式,它的作用是让一个对象在许多行为中选择一种行为。工厂模式在调用的时候是产生多种子类的实现类，而策略模式则都是产生Context类只是运行算法不同。