Refactor: 예약 요청 저장 로직 수정 (#33)

* feat: redis decrement 설정

* feat: 중복 예약 방지를 위한 필드 추가 (유니크 속성에 사용)

* refact: 중복 예약 방지를 위한 필드 추가로 인한 JPA 네이밍 메서드 수정

* refact: 예약 중복 저장시, 예외 발생
* 예약 존재 여부 조회 로직 삭제
* 예외 발생 시, 예약 반호 decr

* refact: 시간대 예약 락 범위 축소 (가게 + 예약 날짜 + 시간대)

* docs: 불필요 주석 삭제

Author: daeyoung0726

src/main/java/com/project/tableforyou/domain/reservationrefactor/entity/QueueReservation.java

@@ -47,6 +47,11 @@ public class QueueReservation extends BaseTimeEntity {
     @Column(name = "is_entered", nullable = false)
     private boolean isEntered = false;
 
+    // 중복 예약 방지 (유니크 설정에 사용)
+    // 예약 취소 또는 입장 완료 시, null로 변경하여 재예약 가능하도록 처리
+    @Column(name = "active_flag")
+    private Boolean activeFlag = true;
+
     // 취소 시각
     @Column(name = "canceled_at")
     private LocalDateTime canceledAt;
@@ -74,6 +79,7 @@ public void cancelReservation() {
         }
 
         this.isCanceled = true;
+        this.activeFlag = null;
         this.canceledAt = LocalDateTime.now();
     }
 
@@ -87,6 +93,7 @@ public void enterRestaurant() {
         }
 
         this.isEntered = true;
+        this.activeFlag = null;
         this.enteredAt = LocalDateTime.now();
     }
 }

src/main/java/com/project/tableforyou/domain/reservationrefactor/entity/TimeSlotReservation.java

@@ -48,6 +48,11 @@ public class TimeSlotReservation extends BaseTimeEntity {
     @Column(name = "is_entered", nullable = false)
     private boolean isEntered = false;
 
+    // 중복 예약 방지 (유니크 설정에 사용)
+    // 예약 취소 또는 입장 완료 시, null로 변경하여 재예약 가능하도록 처리
+    @Column(name = "active_flag")
+    private Boolean activeFlag = true;
+
     // 취소 시각
     @Column(name = "canceled_at")
     private LocalDateTime canceledAt;
@@ -75,6 +80,7 @@ public void cancelReservation() {
         }
 
         this.isCanceled = true;
+        this.activeFlag = null;
         this.canceledAt = LocalDateTime.now();
     }
 
@@ -88,6 +94,7 @@ public void enterRestaurant() {
         }
 
         this.isEntered = true;
+        this.activeFlag = null;
         this.enteredAt = LocalDateTime.now();
     }
 }

src/main/java/com/project/tableforyou/domain/reservationrefactor/redis/RedisRepository.java

@@ -112,4 +112,8 @@ public boolean hashExisted(String key, Object hashKey) {
     public Long increase(String key) {
         return stringRedisTemplate.opsForValue().increment(key);
     }
+
+    public Long decrease(String key) {
+        return stringRedisTemplate.opsForValue().decrement(key);
+    }
 }

src/main/java/com/project/tableforyou/domain/reservationrefactor/redis/queue/QueueReservationRedisService.java

@@ -82,6 +82,11 @@ public int generateNextReservationNumber(Long restaurantId) {
         return number != null ? number.intValue() : 1;
     }
 
+    public void compensateReservationNumber(Long restaurantId) {
+        String key = ReservationConstants.getQueueReservationNumberKey(restaurantId);
+         redisRepository.decrease(key);
+    }
+
     public void markAsEntered(Long userId, Long restaurantId) {
         String key = ReservationConstants.getQueueReservationKey(restaurantId);
         String enteredKey = ReservationConstants.getQueueEnteredCountKey(restaurantId);

src/main/java/com/project/tableforyou/domain/reservationrefactor/redis/timeslot/TimeSlotReservationRedisService.java

@@ -47,6 +47,11 @@ public int generateNextReservationNumber(Long restaurantId, String date, TimeSlo
         return number != null ? number.intValue() : 1;
     }
 
+    public void compensateReservationNumber(Long restaurantId, String date, TimeSlot timeSlot) {
+        String key = ReservationConstants.getTimeSlotReservationNumberKey(restaurantId, date, timeSlot);
+        redisRepository.decrease(key);
+    }
+
     public void cancelReservation(Long userId, Long restaurantId, String date, TimeSlot timeSlot) {
         String key = ReservationConstants.getTimeSlotReservationKey(restaurantId, date, timeSlot);
         redisRepository.hashDel(key, userId);

src/main/java/com/project/tableforyou/domain/reservationrefactor/repository/QueueReservationRepository.java

@@ -9,7 +9,7 @@
 public interface QueueReservationRepository extends JpaRepository<QueueReservation, Long> {
     int countByRestaurantIdAndDate(Long restaurantId, LocalDate date);
 
-    Optional<QueueReservation> findByUserIdAndRestaurantIdAndDateAndIsCanceledFalse(
+    Optional<QueueReservation> findByUserIdAndRestaurantIdAndDateAndIsCanceledFalseAndActiveFlagTrue(
             Long userId, Long restaurantId, LocalDate date
     );
 

src/main/java/com/project/tableforyou/domain/reservationrefactor/repository/TimeSlotReservationRepository.java

@@ -10,7 +10,7 @@
 public interface TimeSlotReservationRepository extends JpaRepository<TimeSlotReservation, Long> {
     int countByRestaurantIdAndDateAndTimeSlotAndIsCanceledFalse(Long restaurantId, LocalDate date, TimeSlot timeSlot);
 
-    Optional<TimeSlotReservation> findByUserIdAndRestaurantIdAndDateAndTimeSlotAndIsCanceledFalse(
+    Optional<TimeSlotReservation> findByUserIdAndRestaurantIdAndDateAndTimeSlotAndIsCanceledFalseAndActiveFlagTrue(
             Long userId, Long restaurantId, LocalDate date, TimeSlot timeSlot
     );
 }

src/main/java/com/project/tableforyou/domain/reservationrefactor/service/ReservationLockManager.java

@@ -37,6 +37,7 @@ public class ReservationLockManager {
      * @return 예약 번호
      */
     public int saveQueueReservation(Long userId, String username, Long restaurantId) {
+        // Lock 범위 : 가게
         String key = ReservationConstants.RESERVATION_KEY_PREFIX + QUEUE + restaurantId;
         RLock lock = redissonClient.getFairLock(LOCK + key);
         try {
@@ -67,7 +68,12 @@ public int saveQueueReservation(Long userId, String username, Long restaurantId)
      * @param createReq    예약 요청 정보 (날짜, 시간, 좌석 수 포함)
      */
     public void saveTimeSlotReservation(Long userId, String username, Long restaurantId, TimeSlotReservationDto.Create createReq) {
-        String key = ReservationConstants.RESERVATION_KEY_PREFIX + TIME_SLOT + restaurantId;
+        // Lock 범위 : 가게 + 예약 날짜 + 시간대
+        String key = ReservationConstants.RESERVATION_KEY_PREFIX
+                + TIME_SLOT
+                + restaurantId + ":"
+                + createReq.date() + ":"
+                + createReq.timeSlot();
         RLock lock = redissonClient.getFairLock(LOCK + key);
 
         try {

src/main/java/com/project/tableforyou/domain/reservationrefactor/service/queue/QueueReservationCacheSyncService.java

@@ -87,7 +87,7 @@ public int getOrLoadCanceledCount(Long restaurantId) {
      */
     public void restoreUserReservationToCache(Long userId, Long restaurantId) {
         Optional<QueueReservation> queueReservation =
-                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalse(
+                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalseAndActiveFlagTrue(
                         userId, restaurantId, LocalDate.now()
                 );
 
@@ -117,7 +117,7 @@ public void restoreUserReservationToCache(Long userId, Long restaurantId) {
     @Transactional
     public int syncUserReservationToCacheIfAbsent(Long userId, Long restaurantId) {
         QueueReservation queueReservation =
-                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalse(
+                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalseAndActiveFlagTrue(
                         userId, restaurantId, LocalDate.now()
                 ).orElseThrow(() -> new CustomException(ErrorCode.RESERVATION_NOT_FOUND));
 

src/main/java/com/project/tableforyou/domain/reservationrefactor/service/queue/QueueReservationCommandService.java

@@ -7,6 +7,7 @@
 import com.project.tableforyou.domain.reservationrefactor.redis.queue.QueueReservationRedisService;
 import com.project.tableforyou.domain.reservationrefactor.repository.QueueReservationRepository;
 import lombok.RequiredArgsConstructor;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -31,14 +32,6 @@ public class QueueReservationCommandService {
      */
     @Transactional
     public int create(Long userId, String username, Long restaurantId) {
-        // Redis에 이미 예약된 사용자라면 예외 발생
-        if (!queueReservationRedisService.isAlreadyReserved(userId, restaurantId)) {
-            // 캐시가 없을 경우 DB에서 확인.
-            queueReservationCacheSyncService.restoreUserReservationToCache(userId, restaurantId);
-        } else {
-            throw new CustomException(ErrorCode.ALREADY_USER_RESERVATION);
-        }
-
         // 예약 번호 계산
         int reservationNumber = getReservationCount(restaurantId);
 
@@ -50,8 +43,14 @@ public int create(Long userId, String username, Long restaurantId) {
                 .date(LocalDate.now())
                 .build();
 
-        // DB에 예약 저장
-        queueReservationRepository.save(queueReservation);
+        try {
+            // DB에 예약 저장
+            queueReservationRepository.save(queueReservation);
+        } catch (DataIntegrityViolationException ex) {
+            // DB 유니크 제약 위반 (중복 예약)
+            queueReservationRedisService.compensateReservationNumber(restaurantId);
+            throw new CustomException(ErrorCode.ALREADY_USER_RESERVATION);
+        }
 
         // Redis에 캐싱
         queueReservationRedisService.saveReservation(
@@ -86,7 +85,7 @@ private int getReservationCount(Long restaurantId) {
     @Transactional
     public void cancel(Long userId, Long restaurantId) {
         QueueReservation queueReservation =
-                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalse(
+                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalseAndActiveFlagTrue(
                         userId, restaurantId, LocalDate.now()
                 ).orElseThrow(() -> new CustomException(ErrorCode.RESERVATION_NOT_FOUND));
 
@@ -102,7 +101,7 @@ public void cancel(Long userId, Long restaurantId) {
     @Transactional
     public void markAsEntered(Long userId, Long restaurantId) {
         QueueReservation queueReservation =
-                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalse(
+                queueReservationRepository.findByUserIdAndRestaurantIdAndDateAndIsCanceledFalseAndActiveFlagTrue(
                         userId, restaurantId, LocalDate.now()
                 ).orElseThrow(() -> new CustomException(ErrorCode.RESERVATION_NOT_FOUND));