[fix] #107 참가자 조회 시 null 반환 제거 및 예외 처리 방식 통일

src/main/java/org/festimate/team/api/facade/FestivalFacade.java

@@ -36,14 +36,13 @@ public FestivalVerifyResponse verifyFestival(FestivalVerifyRequest request) {
     public FestivalInfoResponse getFestivalInfo(Long userId, Long festivalId) {
         User user = userService.getUserByIdOrThrow(userId);
         Festival festival = festivalService.getFestivalByIdOrThrow(festivalId);
-        participantService.validateParticipation(user, festival);
+        participantService.getParticipantOrThrow(user, festival);
         return FestivalInfoResponse.of(festival);
     }
 
     @Transactional
     public FestivalResponse createFestival(Long userId, FestivalRequest request) {
         User host = userService.getUserByIdOrThrow(userId);
-
         festivalService.validateCreateFestival(request);
 
         Festival festival = festivalService.createFestival(host, request);

src/main/java/org/festimate/team/api/facade/ParticipantFacade.java

@@ -77,11 +77,7 @@ public void modifyMessage(Long userId, Long festivalId, MessageRequest request)
     public Participant getParticipant(Long userId, Long festivalId) {
         User user = userService.getUserByIdOrThrow(userId);
         Festival festival = festivalService.getFestivalByIdOrThrow(festivalId);
-        Participant participant = participantService.getParticipant(user, festival);
-        if (participant == null) {
-            throw new FestimateException(ResponseError.PARTICIPANT_NOT_FOUND);
-        }
-        return participant;
+        return participantService.getParticipantOrThrow(user, festival);
     }
 
     @Transactional(readOnly = true)

src/main/java/org/festimate/team/api/facade/PointFacade.java

@@ -26,8 +26,9 @@ public class PointFacade {
 
     @Transactional(readOnly = true)
     public PointHistoryResponse getMyPointHistory(Long userId, Long festivalId) {
+        User user = userService.getUserByIdOrThrow(userId);
         Festival festival = festivalService.getFestivalByIdOrThrow(festivalId);
-        Participant participant = getExistingParticipantOrThrow(userId, festival);
+        Participant participant = participantService.getParticipantOrThrow(user, festival);
         return pointService.getPointHistory(participant);
     }
 
@@ -53,15 +54,6 @@ public void rechargePoints(Long userId, Long festivalId, RechargePointRequest re
         pointService.rechargePoint(participant, request.point());
     }
 
-    private Participant getExistingParticipantOrThrow(Long userId, Festival festival) {
-        User user = userService.getUserByIdOrThrow(userId);
-        Participant participant = participantService.getParticipant(user, festival);
-        if (participant == null) {
-            throw new FestimateException(ResponseError.FORBIDDEN_RESOURCE);
-        }
-        return participant;
-    }
-
     private void isHost(User user, Festival festival) {
         if (!festivalService.isHost(user, festival)) {
             throw new FestimateException(ResponseError.FORBIDDEN_RESOURCE);

src/main/java/org/festimate/team/domain/matching/service/impl/MatchingServiceImpl.java

@@ -17,8 +17,6 @@
 import org.festimate.team.domain.point.service.PointService;
 import org.festimate.team.domain.user.entity.Gender;
 import org.festimate.team.domain.user.service.UserService;
-import org.festimate.team.global.exception.FestimateException;
-import org.festimate.team.global.response.ResponseError;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -42,7 +40,9 @@ public class MatchingServiceImpl implements MatchingService {
     @Transactional
     public MatchingStatusResponse createMatching(Long userId, Long festivalId) {
         Festival festival = festivalService.getFestivalByIdOrThrow(festivalId);
-        Participant participant = getExistingParticipantOrThrow(userId, festival);
+        Participant participant = participantService.getParticipantOrThrow(
+                userService.getUserByIdOrThrow(userId), festival
+        );
 
         isMatchingDateValid(LocalDateTime.now(), festival.getMatchingStartAt());
 
@@ -58,22 +58,14 @@ public MatchingStatusResponse createMatching(Long userId, Long festivalId) {
     @Override
     public MatchingListResponse getMatchingList(Long userId, Long festivalId) {
         Festival festival = festivalService.getFestivalByIdOrThrow(festivalId);
-        Participant participant = getExistingParticipantOrThrow(userId, festival);
+        Participant participant = participantService.getParticipantOrThrow(
+                userService.getUserByIdOrThrow(userId), festival
+        );
 
         List<MatchingInfo> matchings = getMatchingListByParticipant(participant);
         return MatchingListResponse.from(matchings);
     }
 
-    private Participant getExistingParticipantOrThrow(Long userId, Festival festival) {
-        Participant participant = participantService.getParticipant(
-                userService.getUserByIdOrThrow(userId), festival
-        );
-        if (participant == null) {
-            throw new FestimateException(ResponseError.FORBIDDEN_RESOURCE);
-        }
-        return participant;
-    }
-
     @Transactional
     protected Matching saveMatching(Festival festival, Optional<Participant> targetParticipantOptional, Participant participant) {
         Matching matching;

src/main/java/org/festimate/team/domain/participant/service/ParticipantService.java

@@ -15,9 +15,9 @@ public interface ParticipantService {
     @Transactional
     Participant createParticipant(User user, Festival festival, ProfileRequest request);
 
-    Participant getParticipant(User user, Festival festival);
+    Participant getParticipantOrThrow(User user, Festival festival);
 
-    void validateParticipation(User user, Festival festival);
+    Participant getParticipant(User user, Festival festival);
 
     Participant getParticipantById(Long participantId);
 

src/main/java/org/festimate/team/domain/participant/service/impl/ParticipantServiceImpl.java

@@ -18,6 +18,7 @@
 
 import java.time.LocalDate;
 import java.util.List;
+import java.util.Optional;
 
 @Service
 @RequiredArgsConstructor
@@ -46,10 +47,9 @@ public Participant getParticipant(User user, Festival festival) {
     }
 
     @Override
-    public void validateParticipation(User user, Festival festival) {
-        if (getParticipant(user, festival) == null) {
-            throw new FestimateException(ResponseError.PARTICIPANT_NOT_FOUND);
-        }
+    public Participant getParticipantOrThrow(User user, Festival festival) {
+        return Optional.ofNullable(participantRepository.getParticipantByUserAndFestival(user, festival))
+                .orElseThrow(() -> new FestimateException(ResponseError.PARTICIPANT_NOT_FOUND));
     }
 
     @Override

src/test/java/org/festimate/team/api/facade/ParticipantFacadeTest.java

@@ -61,7 +61,7 @@ void setUp() {
     void entryFestival_success() {
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
-        when(participantService.getParticipant(user, festival)).thenReturn(participant);
+        when(participantService.getParticipantOrThrow(user, festival)).thenReturn(participant);
 
         var response = participantFacade.entryFestival(1L, 1L);
 
@@ -86,7 +86,7 @@ void createParticipant_success() {
     void getParticipantProfile_success() {
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
-        when(participantService.getParticipant(user, festival)).thenReturn(participant);
+        when(participantService.getParticipantOrThrow(user, festival)).thenReturn(participant);
 
         var response = participantFacade.getParticipantProfile(1L, 1L);
 
@@ -98,7 +98,7 @@ void getParticipantProfile_success() {
     void getParticipantSummary_success() {
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
-        when(participantService.getParticipant(user, festival)).thenReturn(participant);
+        when(participantService.getParticipantOrThrow(user, festival)).thenReturn(participant);
         when(pointService.getTotalPointByParticipant(participant)).thenReturn(10);
 
         var response = participantFacade.getParticipantSummary(1L, 1L);
@@ -111,7 +111,7 @@ void getParticipantSummary_success() {
     void getParticipantType_success() {
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
-        when(participantService.getParticipant(user, festival)).thenReturn(participant);
+        when(participantService.getParticipantOrThrow(user, festival)).thenReturn(participant);
 
         var response = participantFacade.getParticipantType(1L, 1L);
 
@@ -123,7 +123,7 @@ void getParticipantType_success() {
     void modifyMessage_success() {
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
-        when(participantService.getParticipant(user, festival)).thenReturn(participant);
+        when(participantService.getParticipantOrThrow(user, festival)).thenReturn(participant);
 
         MessageRequest request = new MessageRequest("새로운 소개", "새로운 메세지");
 
@@ -138,7 +138,8 @@ void modifyMessage_success() {
     void getParticipant_fail() {
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
-        when(participantService.getParticipant(user, festival)).thenReturn(null);
+        when(participantService.getParticipantOrThrow(user, festival))
+                .thenThrow(new FestimateException(ResponseError.PARTICIPANT_NOT_FOUND));
 
         assertThatThrownBy(() -> participantFacade.getParticipant(1L, 1L))
                 .isInstanceOf(FestimateException.class)
@@ -148,20 +149,15 @@ void getParticipant_fail() {
     @Test
     @DisplayName("같은 유저가 같은 페스티벌에 중복 참가하려고 하면 예외가 발생해야 한다")
     void createParticipant_duplicate_fail() {
-        // given
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
-        // 이미 참가자가 존재한다고 설정
-        when(participantService.getParticipant(user, festival)).thenReturn(participant);
+        when(participantService.getParticipant(user, festival)).thenReturn(participant); // 이미 존재
 
-        // createParticipant 호출 시 예외를 직접 발생시키도록 설정
-        when(participantService.createParticipant(any(), any(), any()))
-                .thenThrow(new FestimateException(ResponseError.PARTICIPANT_ALREADY_EXISTS));
-
-        // when & then
         assertThatThrownBy(() -> participantFacade.createParticipant(1L, 1L,
                 new ProfileRequest(TypeResult.HEALING, "자기소개", "메시지")))
                 .isInstanceOf(FestimateException.class)
                 .hasMessageContaining(ResponseError.PARTICIPANT_ALREADY_EXISTS.getMessage());
+
+        verify(participantService, never()).createParticipant(any(), any(), any());
     }
 }

src/test/java/org/festimate/team/api/facade/PointFacadeTest.java

@@ -62,7 +62,7 @@ void getMyPointHistory_success() {
         // given
         when(festivalService.getFestivalByIdOrThrow(100L)).thenReturn(festival);
         when(userService.getUserByIdOrThrow(2L)).thenReturn(participantUser);
-        when(participantService.getParticipant(participantUser, festival)).thenReturn(participant);
+        when(participantService.getParticipantOrThrow(participantUser, festival)).thenReturn(participant);
 
         PointHistoryResponse dummyResponse = PointHistoryResponse.from(5, List.of());
         when(pointService.getPointHistory(participant)).thenReturn(dummyResponse);

src/test/java/org/festimate/team/domain/matching/service/impl/MatchingServiceImplTest.java

@@ -84,7 +84,7 @@ void getMatchingList_success() {
 
         when(festivalService.getFestivalByIdOrThrow(1L)).thenReturn(festival);
         when(userService.getUserByIdOrThrow(1L)).thenReturn(user);
-        when(participantService.getParticipant(user, festival)).thenReturn(participant);
+        when(participantService.getParticipantOrThrow(user, festival)).thenReturn(participant);
         when(matchingRepository.findAllMatchingsByApplicantParticipant(participant))
                 .thenReturn(List.of(matching2, matching1));