@Configuration과 싱글톤

@Configuration과 싱글톤

AppConfig 코드를 보면

@Configuration
public class AppConfig {
    @Bean
    public MemberService memberService() {
        return new MemberServiceImpl(memberRepository());
    }
    @Bean
    public OrderService orderService() {
        return new OrderServiceImpl(
                memberRepository(),
                discountPolicy());
    }
    @Bean
    public MemberRepository memberRepository() {
        return new MemoryMemberRepository();
    }
    @Bean
    public DiscountPolicy discountPolicy() {
        return new RateDiscountPolicy();
    }
}

 

 

 

검증 용도의 코드 추가 1 - MemberServiceImpl

public class MemberServiceImpl implements MemberService {

    private final MemberRepository memberRepository; // 수정

    public MemberServiceImpl(MemberRepository memberRepository) {
        this.memberRepository = memberRepository;
    }

    @Override
    public void join(Member member) {
        memberRepository.save(member);
    }


    //테스트 용도 추가
    public MemberRepository getMemberRepository() {
        return memberRepository;
    }


    @Override
    public Member findMember(Long memberId) {
        return memberRepository.findById(memberId);
    }

}

 

검증 용도의 코드 추가 2 - OrderServiceImpl

public class OrderServiceImpl implements OrderService {

    private final MemberRepository memberRepository;

    private final DiscountPolicy discountPolicy; 

    //테스트 용도 추가
    public MemberRepository getMemberRepository() {
        return memberRepository;
    }


    
    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);
    }
}

 

 

테스트 코드 - ConfigurationSingletonTest

package inflearn.spring_core.singleton;

import inflearn.spring_core.config.AppConfig;
import inflearn.spring_core.member.MemberRepository;
import inflearn.spring_core.member.MemberServiceImpl;
import inflearn.spring_core.order.OrderServiceImpl;
import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import static org.assertj.core.api.Assertions.assertThat;

public class ConfigurationSingletonTest {
    @Test
    void configurationTest() {

        ApplicationContext ac = new AnnotationConfigApplicationContext(AppConfig.class);
        
        MemberServiceImpl memberService = ac.getBean("memberService", MemberServiceImpl.class);
        OrderServiceImpl orderService = ac.getBean("orderService", OrderServiceImpl.class);
        MemberRepository memberRepository = ac.getBean("memberRepository", MemberRepository.class);

        // 각각의 서비스와 레포지토리가 같은 인스턴스를 참조하고 있는지 확인
        System.out.println("memberService -> memberRepository = " + memberService.getMemberRepository());
        System.out.println("orderService -> memberRepository = " + orderService.getMemberRepository());
        System.out.println("memberRepository = " + memberRepository);

        //모두 같은 인스턴스를 참고하고 있다.
        assertThat(memberService.getMemberRepository()).isSameAs(memberRepository);
        assertThat(orderService.getMemberRepository()).isSameAs(memberRepository);
    }
}

 

실행 결과

같은 인스턴스 참고중.

 

그런데,

AppConfig의 자바 코드를 보면 분명히 각각 2번 `new MemoryMemberRepository` 호출해서 다른 인스턴스가 생성되어야 하는데?

 

AppConfig에 호출 로그를 남긴다.

package inflearn.spring_core.config;

import inflearn.spring_core.discount.DiscountPolicy;
import inflearn.spring_core.discount.RateDiscountPolicy;
import inflearn.spring_core.member.MemberRepository;
import inflearn.spring_core.member.MemberService;
import inflearn.spring_core.member.MemberServiceImpl;
import inflearn.spring_core.member.MemoryMemberRepository;
import inflearn.spring_core.order.OrderService;
import inflearn.spring_core.order.OrderServiceImpl;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

// 애플리케이션의 전체 동작 방식을 구성(config)하기 위해, 구현 객체를 생성하고, 연결하는 책임을 가지는 별도의 설정 클래스
@Configuration
public class AppConfig {
    @Bean
    public MemberService memberService() {
        // 여기
        System.out.println("call AppConfig.memberService");
        return new MemberServiceImpl(memberRepository());
    }

    @Bean
    public OrderService orderService() {
        // 여기
        System.out.println("call AppConfig.orderService");
        return new OrderServiceImpl(
                memberRepository(),
                discountPolicy());
    }
    @Bean
    public MemberRepository memberRepository() {
        // 여기
        System.out.println("call AppConfig.memberRepository");
        return new MemoryMemberRepository();
    }

    @Bean
    public DiscountPolicy discountPolicy() {
        return new RateDiscountPolicy();
    }
}

 

 

그런데 출력 결과

모두 한 번만 출력이 된다.

 

원래 에상 결과는 이렇게 되어야 할 것인데...

 

왜 그런지는 다음 포스트에서!