11. 주문과 할인 도메인 개발

할인 정책 인터페이스

package hello.core.discount;

import hello.core.member.Member;

public interface DiscountPolicy {


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


}

 

 

정액 할인 정책 구현체

- VIP면 1000원 할인, 아니면 할인 없음

package hello.core.discount;

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

public class FixDiscountPolicy implements DiscountPolicy{

    private int discountFixAmount = 1000; // 1000원 할인

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

    }
}

---

 

 

주문 엔티티

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 +
                '}';
    }
}

 

주문 서비스 인터페이스

package hello.core.order;

public interface OrderService {

    order createOrder (long memberId, String itemName, int itemPrice);
}

 

주문 서비스 구현체

- 주문 생성 요청이 오면, 회원 정보를 조회하고, 할인 정책을 적용한 다음 주문 객체를 생성해서 반환한다.
- 메모리 회원 리포지토리와, 고정 금액 할인 정책을 구현체로 생성한다.

package hello.core.order;

import hello.core.discount.DiscountPolicy;
import hello.core.discount.FixDiscountPolicy;
import hello.core.member.Member;
import hello.core.member.MemberRepository;
import hello.core.member.MemberService;
import hello.core.member.MemoryMemberRepository;

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) {
        
        // 회원정보 조회
        Member member = memberRepository.findById(memberId);
        
        // 할인정책에 멤버 정보 넘기고 최종 할인가격 받아옴
        int discountPrice = discountPolicy.discount(member, itemPrice);

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