设计模式-行为型-策略模式

1、定义

策略模式：定义一系列算法，把它们封装起来，并且使它们可以互相替换

写法

public interface IMemberStrategy {
    //打折
    double discount(double price);
}

public class AdvancedMemberStrategy implements IMemberStrategy {
    @Override
    public double discount(double price) {
        return price * 0.8;
    }
}

public class IntermediateMemberStrategy implements IMemberStrategy {
    @Override
    public double discount(double price) {
        return price * 0.9;
    }
}

public class PrimaryMemberStrategy implements IMemberStrategy {
    @Override
    public double discount(double price) {
        return price * 1;
    }
}

public class Price {
    private IMemberStrategy strategy;

    public Price(IMemberStrategy strategy){
        this.strategy = strategy;
    }

    public double quote(double booksPrice){
        return strategy.discount(booksPrice);
    }

}

/**
 * 策略模式
 * 关注点在于行为的选择
 * 解决swich-case
 */
public class TestMain {

    public static void main(String[] args) {

        Price price = new Price( new PrimaryMemberStrategy() );
        price.quote( 100 );

        Price price1 = new Price( new IntermediateMemberStrategy() );
        price.quote( 100 );

        Price price2 = new Price( new AdvancedMemberStrategy() );
        price.quote( 100 );

    }

}

代码示例

https://github.com/yinlingchaoliu/23-design-pattern