Spring 학습 예제 - 2

주문과 할인 도메인 설계

주문과 할인 정책

• 회원은 상품을 주문할 수 있다.
• 회원 등급에 따라 할인 정책을 적용할 수 있다.
• 할인 정책은 모든 VIP는 1000원을 할인해주는 고정 금액 할인을 적용(나중에 변경 될 수 있다.)
• 할인 정책은 변경 가능성이 높다. 회사의 기본 할인 정책을 아직 정하지 못했고, 오픈 직전까지 고민을 미루고 싶다.
• 최악의 경우 할인을 적용하지 않을 수 도 있다.(미확정)

1. 주문생성
2. 회원조회
3. 할인적용
4. 주문결과반환

<<interface>>DicountPolicy
FixDiscountPolicy
RateDiscountPolicy

주문과 할인 도메인 개발

DIcountPolicy.java

package hello.core.dicount;

import hello.core.Member.Member;

public interface DiscountPolicy {

    /**
     * @return 할인 대상 금액
     */
    int discount(Member member, int price);
}

FixDiscountPolicy.java

package hello.core.dicount;

import hello.core.Member.Grade;
import hello.core.Member.Member;

public class FixDiscountPolicy implements DiscountPolicy{

    private int discountFixAmount = 1000;

    @Override
    public int discount(Member member, int price) {
        if(member.getGrade() == Grade.VIP){
            return discountFixAmount;
        }else{
            return 0;
        }
    }
}

Order.java

package hello.core.order;

public class Order {

    private Long memberId;
    private String itemName;
    private int itemPrice;
    private int discountPrice;

    public Order(Long memberId, String itemName, int itemPrice, int discountPrice) {
        this.memberId = memberId;
        this.itemName = itemName;
        this.itemPrice = itemPrice;
        this.discountPrice = discountPrice;
    }

    public int calculatePrice() {
        return itemPrice - discountPrice;
    }

    public Long getMemberId() {
        return memberId;
    }

    public void setMemberId(Long memberId) {
        this.memberId = memberId;
    }

    public String getItemName() {
        return itemName;
    }

    public void setItemName(String itemName) {
        this.itemName = itemName;
    }

    public int getItemPrice() {
        return itemPrice;
    }

    public void setItemPrice(int itemPrice) {
        this.itemPrice = itemPrice;
    }

    public int getDiscountPrice() {
        return discountPrice;
    }

    public void setDiscountPrice(int discountPrice) {
        this.discountPrice = discountPrice;
    }

    @Override
    public String toString() {
        return "Order{" +
                "memberId=" + memberId +
                ", itemName='" + itemName + '\'' +
                ", itemPrice=" + itemPrice +
                ", discountPrice=" + discountPrice +
                '}';
    }
}

OrderService.java

package hello.core.order;

public interface OrderService {
    Order createOrder(Long memberId, String itemName, int itemPrice);
}

OrderServiceImpl.java

package hello.core.order;

import hello.core.Member.Member;
import hello.core.Member.MemberRepository;
import hello.core.Member.MemoryMemberRepository;
import hello.core.dicount.DiscountPolicy;
import hello.core.dicount.FixDiscountPolicy;

public class OrderServiceImpl implements OrderService{

    private final MemberRepository memberRepository = new MemoryMemberRepository();
    private final DiscountPolicy discountPolicy = new FixDiscountPolicy();

    @Override
    public Order createOrder(Long memberId, String itemName, int itemPrice) {
        Member member = memberRepository.findById(memberId);
        int discountPrice = discountPolicy.discount(member, itemPrice);

        return new Order(memberId, itemName, itemPrice, discountPrice);
    }
}

주문과 할인 도메인 실행과 테스트

OrderApp.java

package hello.core;

import hello.core.Member.Grade;
import hello.core.Member.Member;
import hello.core.Member.MemberService;
import hello.core.Member.MemberServiceImpl;
import hello.core.order.Order;
import hello.core.order.OrderService;
import hello.core.order.OrderServiceImpl;

public class OrderApp {

    public static void main(String[] args) {
        MemberService memberService = new MemberServiceImpl();
        OrderService orderService = new OrderServiceImpl();

        Long memberId = 1L;
        Member member = new Member(memberId, "memberA", Grade.VIP);
        memberService.join(member);

        Order order = orderService.createOrder(memberId, "itemA", 10000);

        System.out.println("order = " + order);
    }
}

OrderServiceTest.java

package hello.core.order;

import hello.core.Member.Grade;
import hello.core.Member.Member;
import hello.core.Member.MemberService;
import hello.core.Member.MemberServiceImpl;
import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.Test;

public class OrderServiceTest {

    MemberService memberService = new MemberServiceImpl();
    OrderService orderService = new OrderServiceImpl();

    @Test
    void createOrder() {
        Long memberId = 1L;
        Member member = new Member(memberId, "memberA", Grade.VIP);
        memberService.join(member);

        Order order = orderService.createOrder(memberId, "itemA", 10000);
        Assertions.assertThat(order.getDiscountPrice()).isEqualTo(1000);

    }

}