Merge pull request #216 from prgrms-web-devcourse-final-project/ajh/event/concurrent_test

이벤트 참여 시 비관적 락으로 로직 수행

Author: june3780

src/main/java/com/grepp/spring/app/model/event/repository/EventMemberRepository.java

@@ -2,11 +2,13 @@
 
 import com.grepp.spring.app.model.event.entity.Event;
 import com.grepp.spring.app.model.event.entity.EventMember;
+import jakarta.persistence.LockModeType;
 import java.util.ArrayList;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 import java.util.List;
 import java.util.Optional;
+import org.springframework.data.jpa.repository.Lock;
 
 public interface EventMemberRepository extends JpaRepository<EventMember, Long> {
 
@@ -21,4 +23,6 @@ public interface EventMemberRepository extends JpaRepository<EventMember, Long>
     ArrayList<EventMember> findByEvent(Event event);
 
     void deleteByEventAndMemberId(Event event, String id);
+
+    List<EventMember> findByEventId(Long eventId);
 }

src/main/java/com/grepp/spring/app/model/event/repository/EventRepository.java

@@ -1,8 +1,13 @@
 package com.grepp.spring.app.model.event.repository;
 
 import com.grepp.spring.app.model.event.entity.Event;
+import jakarta.persistence.LockModeType;
 import java.util.ArrayList;
+import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Lock;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 
 
@@ -11,4 +16,8 @@ public interface EventRepository extends JpaRepository<Event, Long> {
 
 
     ArrayList<Event> findByGroupId(Long groupId);
+
+    @Lock(LockModeType.PESSIMISTIC_WRITE)
+    @Query("SELECT e FROM Event e WHERE e.id = :eventId")
+    Optional<Event> findEventForUpdate(@Param("eventId") Long eventId);
 }

src/main/java/com/grepp/spring/app/model/event/service/EventCommandService.java

@@ -65,7 +65,10 @@ public CreateEventResponse createEvent(CreateEventRequest webRequest, String cur
     public void joinEvent(Long eventId, Long groupId, String currentMemberId) {
         JoinEventDto dto = JoinEventDto.toDto(eventId, currentMemberId);
 
-        Event event = findEventOrThrow(dto.getEventId());
+        //Event event = findEventOrThrow(dto.getEventId());
+
+        // 비관적락
+        Event event = findEventWithLockOrThrow(dto.getEventId());
         Member member = findMemberOrThrow(dto.getMemberId());
 
         validateEventMemberIsAlreadyJoined(dto.getEventId(), dto.getMemberId());
@@ -175,6 +178,11 @@ private Event findEventOrThrow(Long eventId) {
             .orElseThrow(() -> new EventNotFoundException(EventErrorCode.EVENT_NOT_FOUND));
     }
 
+    private Event findEventWithLockOrThrow(Long eventId) {
+        return eventRepository.findEventForUpdate(eventId)
+            .orElseThrow(() -> new EventNotFoundException(EventErrorCode.EVENT_NOT_FOUND));
+    }
+
     private Member findMemberOrThrow(String memberId) {
         return memberRepository.findById(memberId)
             .orElseThrow(() -> new EventNotFoundException(EventErrorCode.MEMBER_NOT_FOUND));