MemberService 회원 조회 시간 측정 추가

<MemberService.java>

package hello.hello_spring.service;

import hello.hello_spring.domain.Member;
import hello.hello_spring.repository.MemberRepository;
import hello.hello_spring.repository.MemoryMemberRepository;
import jakarta.transaction.Transactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Optional;

@Transactional

@Service
public class MemberService {

    private final MemberRepository memberRepository;

    @Autowired
    public MemberService(MemberRepository memberRepository){
        this.memberRepository = memberRepository;
    }

    // 회원가입
    public Long join(Member member) {
        long start = System.currentTimeMillis();

        try{
            validateDuplicateMember(member);    // 중복 회원 검증
            memberRepository.save(member);
            return member.getId();         // id 반환하기
        } finally {
            long finish = System.currentTimeMillis();
            long timeMs = finish - start;
            System.out.println("join " + timeMs + "ms");
        }

    }

    private void validateDuplicateMember(Member member) {
        memberRepository.findByName(member.getName())
                       .ifPresent(m -> {
        throw new IllegalStateException("이미 존재하는 회원입니다.");
                       });
    }

    // 전체 회원 조회
    public List<Member> findMembers() {
        long start = System.currentTimeMillis();
        try {
            return memberRepository.findAll();
        }
        finally {
            long finish = System.currentTimeMillis();
            long timeMs = finish - start;
            System.out.println("findMembers " + timeMs + "ms");
        }
    }

    public Optional<Member> findOne(Long memberId){
        return memberRepository.findById(memberId);
    }

    private Optional<Member> getByName(Member member) {
        return memberRepository.findByName(member.getName());
    }
}

추가 학습

AOP란?!

• aspect-oriented programming의 약자로 관점 지향 프로그래밍
• 객체 지향 프로그래밍(OPP)에서 모듈화의 핵심 단위가 “클래스”라고 한다면, AOP에서의 핵심 단위는 “관점”이다.
• 반복되고 공통적으로 사용되는 부분을 분리함으로써 모듈성을 증가시키는 프로그래밍 방법