OOP 회원과 주문 관리 설계

CNOW 2024. 12. 19. 16:46

요약

의존성 주입을 통해 객체 간의 결합도를 낮춥니다.
싱글톤 패턴을 사용하여 인스턴스를 공유합니다.
관심사 분리를 통해 설정과 비즈니스 로직을 분리하여 코드의 유지보수성을 높입니다.
AppConfig를 통해 필요한 객체를 주입 받습니다.

오늘은 객체 지향 설계를 할 수 있도록 연습해보는 코드를 작성해보겠습니다.

회원 가입 시스템 설계

package member;

public enum Grade {
	BASIC, VIP
}

package member;

public class Member {

	private Long id;
	private String name;
	private Grade grade;

	public Member(Long id, String name, Grade grade) {
		this.id = id;
		this.name = name;
		this.grade = grade;
	}

	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Grade getGrade() {
		return grade;
	}

	public void setGrade(Grade grade) {
		this.grade = grade;
	}


}

Repository

package member.repository;

import member.Member;

public interface MemberRepsitory {

	void save(Member member);
	Member findById(Long memberId);
}

package member.repository;

import member.Grade;
import member.Member;

import java.util.HashMap;
import java.util.Map;

public class MemoryMemberRepositoryImpl implements MemberRepository {

    private static MemoryMemberRepositoryImpl instance;
    private Map<Long, Member> memberStore;

    private MemoryMemberRepositoryImpl() {
        memberStore = new HashMap<Long, Member>();
        initData();
    }

    @Override
    public void save(Member member) {
        memberStore.put(member.getId(), member);
    }

    @Override
    public Member findById(Long id) {
        return memberStore.get(id);
    }

    public static MemoryMemberRepositoryImpl getInstance() {
        if (instance == null) {
            instance = new MemoryMemberRepositoryImpl();
        }
        return instance;
    }

// 샘플 초기 데이터private void initData() {
        memberStore.put(1L, new Member(1L, "홍길동", Grade.VIP));
        memberStore.put(2L, new Member(2L, "성춘향", Grade.VIP));
        memberStore.put(3L, new Member(3L, "이몽룡", Grade.BASIC));
    }
}

package member.repository;

import member.Member;

public class DBMemberRepositoryImpl implements MemberRepository {



    @Override
    public void save(Member member) {

    }

    @Override
    public Member findById(Long id) {
        return null;
    }
}

Service

package member.service;

import member.Member;

public interface MemberService {

    void signUp(Member member);

    Member findByIdMember(Long memberId);

}

package member.service;

import member.Member;
import member.repository.MemberRepository;

public class MemberServiceImpl implements MemberService {

    private MemberRepository repository;

// 생성자 의존 주입public MemberServiceImpl(MemberRepository repository) {
        this.repository = repository;
    }

    @Override
    public void signUp(Member member) {
        repository.save(member);
    }

    @Override
    public Member findByIdMember(Long memberId) {
        return repository.findById(memberId);
    }
}

Main Class

package member;

import member.repository.MemberRepository;
import member.repository.MemoryMemberRepositoryImpl;
import member.service.MemberService;
import member.service.MemberServiceImpl;

public class MainTest1 {

    public static void main(String[] args) {

        MemberRepository memberRepository = MemoryMemberRepositoryImpl.getInstance();

        MemberService memberService = new MemberServiceImpl(memberRepository);

// 클라이언트
        Member member = new Member(100L, "티모", Grade.VIP);

// 신규 회원가입
        memberService.signUp(member);

        System.out.println(memberService.findByIdMember(100L).toString());
        System.out.println(memberService.findByIdMember(1L).toString());
        System.out.println(memberService.findByIdMember(2L).toString());
        System.out.println(memberService.findByIdMember(3L).toString());
    }

}

심화 - 할인율

package order;

import member.Member;

public interface DiscountPolicy {

    int discount(Member member, int price);

}

고정 할인율

package order;

import member.Grade;
import member.Member;

public class FixDiscountPolicyImpl implements DiscountPolicy {

    private int discountFixAmount = 1500;

    @Override
    public int discount(Member member, int price) {
// VIP 회원만 할인 금액 적용 된다.if(member.getGrade() == Grade.VIP) {
            return discountFixAmount;
        }
        return 0;
    }

}

변동 할인율

package order;

import member.Grade;
import member.Member;

public class PercentDiscountPolicyImpl implements DiscountPolicy {

    private double discountPercent = 10.0;

    @Override
    public int discount(Member member, int price) {
        if(member.getGrade() == Grade.VIP) {
            return (int)(price * (discountPercent / 100));
        }
        return 0;
    }

}

객체

package 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;
    }

// 상품 금액에 할인된 가격 금액 출력 하는 기능public int calculateDiscount() {
        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 +
                '}';
    }
}

서비스

package order;

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

서비스 구현체

package order;

import member.Member;
import member.repository.MemberRepository;

public class OrderServiceImpl implements OrderService {

    private final MemberRepository memberRepository;
    private final DiscountPolicy discountPolicy;

    public OrderServiceImpl(MemberRepository memberRepository, DiscountPolicy discountPolicy) {
        this.memberRepository = memberRepository;
        this.discountPolicy = discountPolicy;
    }

    @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);
    }
}

Main Class

package order;

import member.Grade;
import member.Member;
import member.repository.MemberRepository;
import member.repository.MemoryMemberRepositoryImpl;

public class OrderServiceTest {

    public static void main(String[] args) {

        MemberRepository memberRepository = MemoryMemberRepositoryImpl.getInstance();

        Member member = new Member(10L, "변영준", Grade.VIP);

// 공정 할인 정책 테스트
        DiscountPolicy fixDiscountPolicy = new FixDiscountPolicyImpl();
        DiscountPolicy percentDiscountPolicy = new PercentDiscountPolicyImpl();
        OrderService orderService1 = new OrderServiceImpl(memberRepository, fixDiscountPolicy);

        Order order1 = orderService1.createOrder(1L, "맥북", 10000);
        System.out.println(order1);
        System.out.println(order1.calculateDiscount());


    }

}

심화 2 - Configuration 설정

package config;

import member.repository.MemberRepository;
import member.repository.MemoryMemberRepositoryImpl;
import member.service.MemberService;
import member.service.MemberServiceImpl;
import order.*;

public class AppConfig {

    public MemberRepository getMemberRepository() {
        return MemoryMemberRepositoryImpl.getInstance();
    }

    public MemberService getMemberService() {
        return new MemberServiceImpl(getMemberRepository());
    }

    public DiscountPolicy getDiscountPolicy() {
// 이 부분만 바꾸면 됨// return new FixDiscountPolicyImpl();return  new PercentDiscountPolicyImpl();
    }

    public OrderService getOrderService() {
        return new OrderServiceImpl(getMemberRepository(), getDiscountPolicy());
    }

}

Main Class

package config;

import member.Grade;
import member.Member;
import member.service.MemberService;
import order.Order;
import order.OrderService;

public class MainApp {

    public static void main(String[] args) {


        AppConfig appConfig = new AppConfig();

// 클라이언트 입장에서 코딩// 회원 가입 기능이 필요함.
        MemberService memberService = appConfig.getMemberService();
        Member member = new Member(200L, "도시락", Grade.VIP);
        memberService.signUp(member);// 회원 가입// 사용자 주문 요청
        OrderService orderService1 = appConfig.getOrderService();
        Order order1 = orderService1.createOrder(member.getId(), "아이폰16", 3_000);
        System.out.println(order1);
        System.out.println(order1.calculateDiscount());

    }

}