Java设计模式之策略模式详细解析

public interface Member {

    public void discount();
}

public class JuniorMember implements Member{
    @Override
    public void discount() {
        System.out.println("初级会员打9折");
    }
}

public class AssociateMember implements Member{
    @Override
    public void discount() {
        System.out.println("中级会员打8折");
    }
}

public class SeniorMember implements Member{
    @Override
    public void discount() {
        System.out.println("高级会员打7折");
    }
}

public class DiscountService {
    Member member;
    public void payment(MemberType memberType){
        if(memberType==MemberType.JUNIOR){
            member = new JuniorMember();
            member.discount();
        }else if(memberType==MemberType.ASSOCIATE){
            member = new AssociateMember();
            member.discount();
        } else if (memberType==MemberType.SENIOR) {
            member = new SeniorMember();
            member.discount();
        }
    }
}

enum MemberType{
    ASSOCIATE,
    JUNIOR,
    SENIOR
}

public class Client {
    public static void main(String[] args){
        DiscountService discountService = new DiscountService();
        System.out.println("--------------使用传统模式--------------");
        discountService.payment(MemberType.SENIOR);
        discountService.payment(MemberType.ASSOCIATE);
        discountService.payment(MemberType.JUNIOR);
    }
}
/**
 * --------------使用传统模式--------------
 * 高级会员打7折
 * 中级会员打8折
 * 初级会员打9折
 */

public class DiscountService {
    Member member;

    DiscountService(Member member){
        this.member = member;
    }

    public void setMember(Member member) {
        this.member = member;
    }

    public void payment(){
        member.discount();
    }
}

public class Client {
    public static void main(String[] args) {
        System.out.println("------------使用策略模式------------");
        DiscountService discountService = new DiscountService(new JuniorMember());
        discountService.payment();
        discountService.setMember(new AssociateMember());
        discountService.payment();
        discountService.setMember(new SeniorMember());
        discountService.payment();
    }
}
/**
 * ------------使用策略模式------------
 * 初级会员打9折
 * 中级会员打8折
 * 高级会员打7折
 */