Feature: 락을 활용하여 동시성 문제가 일어나지 않는 예매 기능을 구현한다.

src/main/java/com/thirdparty/ticketing/domain/common/ErrorCode.java

@@ -42,6 +42,13 @@ public enum ErrorCode {
     */
     NOT_FOUND_SEAT_GRADE(HttpStatus.NOT_FOUND, "SG404-1", "존재하지 않는 구역입니다."),
 
+    /*
+       Seat Error
+    */
+    NOT_FOUND_SEAT(HttpStatus.NOT_FOUND, "S404-1", "존재하지 않는 좌석입니다."),
+    NOT_SELECTABLE_SEAT(HttpStatus.FORBIDDEN, "S403-1", "이미 선택된 좌석입니다."),
+    INVALID_SEAT_STATUS(HttpStatus.FORBIDDEN, "S403-2", "해당 좌석에는 접근할 수 없습니다."),
+
     /*
        Payment Error
     */
@@ -51,7 +58,8 @@ public enum ErrorCode {
        Waiting Error
     */
     WAITING_WRITE_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "W500-1", "대기열 쓰기에 실패했습니다."),
-    WAITING_READ_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "W500-2", "대기열 읽기에 실패했습니다.");
+    WAITING_READ_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "W500-2", "대기열 읽기에 실패했습니다."),
+    ;
 
     ErrorCode(HttpStatus httpStatus, String code, String message) {
         this.httpStatus = httpStatus;

src/main/java/com/thirdparty/ticketing/domain/common/Event.java

@@ -0,0 +1,3 @@
+package com.thirdparty.ticketing.domain.common;
+
+public interface Event {}

src/main/java/com/thirdparty/ticketing/domain/common/EventPublisher.java

@@ -0,0 +1,6 @@
+package com.thirdparty.ticketing.domain.common;
+
+public interface EventPublisher {
+
+    void publish(Event event);
+}

src/main/java/com/thirdparty/ticketing/domain/common/LettuceRepository.java

@@ -0,0 +1,24 @@
+package com.thirdparty.ticketing.domain.common;
+
+import java.time.Duration;
+
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.stereotype.Repository;
+
+import lombok.RequiredArgsConstructor;
+
+@Repository
+@RequiredArgsConstructor
+public class LettuceRepository {
+    private final StringRedisTemplate redisTemplate;
+
+    // 1. lock을 생성
+    // 2. 60초가 유지되는 key는 자리번호 value는 유저 id를 생성
+    public Boolean seatLock(String key) {
+        return redisTemplate.opsForValue().setIfAbsent(key, "lock", Duration.ofMinutes(1));
+    }
+
+    public void unlock(String string) {
+        redisTemplate.delete(string);
+    }
+}

src/main/java/com/thirdparty/ticketing/domain/member/Member.java

@@ -1,6 +1,7 @@
 package com.thirdparty.ticketing.domain.member;
 
 import java.time.ZonedDateTime;
+import java.util.Objects;
 
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
@@ -53,4 +54,17 @@ public Member(String email, String password, MemberRole memberRole, ZonedDateTim
         this.password = password;
         this.memberRole = memberRole;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Member member = (Member) o;
+        return Objects.equals(memberId, member.memberId);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(memberId);
+    }
 }

src/main/java/com/thirdparty/ticketing/domain/seat/Seat.java

@@ -3,6 +3,8 @@
 import jakarta.persistence.*;
 
 import com.thirdparty.ticketing.domain.BaseEntity;
+import com.thirdparty.ticketing.domain.common.ErrorCode;
+import com.thirdparty.ticketing.domain.common.TicketingException;
 import com.thirdparty.ticketing.domain.member.Member;
 import com.thirdparty.ticketing.domain.zone.Zone;
 
@@ -11,13 +13,15 @@
 import lombok.Builder;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 
 @Entity
 @Table(name = "seat")
 @Getter
 @Builder
 @AllArgsConstructor
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Slf4j
 public class Seat extends BaseEntity {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
@@ -43,6 +47,8 @@ public class Seat extends BaseEntity {
     @Column(length = 16, nullable = false)
     private SeatStatus seatStatus = SeatStatus.SELECTABLE;
 
+    @Version private Long version;
+
     public Seat(String seatCode, SeatStatus seatStatus) {
         this.seatCode = seatCode;
         this.seatStatus = seatStatus;
@@ -51,4 +57,31 @@ public Seat(String seatCode, SeatStatus seatStatus) {
     public boolean isSelectable() {
         return seatStatus.isSelectable();
     }
+
+    public void assignByMember(Member member) {
+        if (!isSelectable()) {
+            throw new TicketingException(ErrorCode.NOT_SELECTABLE_SEAT);
+        }
+        log.info("seat occupied by {}", member.getEmail());
+        this.member = member;
+        this.seatStatus = SeatStatus.SELECTED;
+    }
+
+    public void markAsPendingPayment() {
+        if (!seatStatus.isSelected()) {
+            throw new TicketingException(ErrorCode.INVALID_SEAT_STATUS);
+        }
+        this.seatStatus = SeatStatus.PENDING_PAYMENT;
+    }
+
+    public void markAsPaid() {
+        if (!seatStatus.isPendingPayment()) {
+            throw new TicketingException(ErrorCode.INVALID_SEAT_STATUS);
+        }
+        this.seatStatus = SeatStatus.PAID;
+    }
+
+    public boolean isAssignedByMember(Member loginMember) {
+        return loginMember.equals(member);
+    }
 }

src/main/java/com/thirdparty/ticketing/domain/seat/SeatStatus.java

@@ -9,4 +9,16 @@ public enum SeatStatus {
     public boolean isSelectable() {
         return this == SELECTABLE;
     }
+
+    public boolean isSelected() {
+        return this == SELECTED;
+    }
+
+    public boolean isPendingPayment() {
+        return this == PENDING_PAYMENT;
+    }
+
+    public boolean isPaid() {
+        return this == PAID;
+    }
 }

src/main/java/com/thirdparty/ticketing/domain/seat/repository/SeatRepository.java

@@ -1,14 +1,33 @@
 package com.thirdparty.ticketing.domain.seat.repository;
 
 import java.util.List;
+import java.util.Optional;
+
+import jakarta.persistence.LockModeType;
 
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Lock;
+import org.springframework.data.jpa.repository.Query;
 import org.springframework.stereotype.Repository;
 
 import com.thirdparty.ticketing.domain.seat.Seat;
 import com.thirdparty.ticketing.domain.zone.Zone;
 
+import io.lettuce.core.dynamic.annotation.Param;
+
 @Repository
 public interface SeatRepository extends JpaRepository<Seat, Long> {
     List<Seat> findByZone(Zone zone);
+
+    @Query("SELECT s FROM Seat as s WHERE s.id = :seatId")
+    @Lock(LockModeType.NONE)
+    Optional<Seat> findById(@Param("seatId") Long seatId);
+
+    @Query("SELECT s FROM Seat as s WHERE s.id = :seatId")
+    @Lock(LockModeType.OPTIMISTIC)
+    Optional<Seat> findByIdWithOptimistic(@Param("seatId") Long seatId);
+
+    @Query("SELECT s FROM Seat as s WHERE s.id = :seatId")
+    @Lock(LockModeType.PESSIMISTIC_WRITE)
+    Optional<Seat> findByIdWithPessimistic(@Param("seatId") Long seatId);
 }

src/main/java/com/thirdparty/ticketing/domain/ticket/controller/TicketController.java

@@ -1,45 +1,50 @@
 package com.thirdparty.ticketing.domain.ticket.controller;
 
+import java.util.List;
+
 import jakarta.validation.Valid;
 
 import org.springframework.http.ResponseEntity;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.PostMapping;
-import org.springframework.web.bind.annotation.RequestBody;
-import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.bind.annotation.*;
 
 import com.thirdparty.ticketing.domain.ItemResult;
 import com.thirdparty.ticketing.domain.common.LoginMember;
 import com.thirdparty.ticketing.domain.ticket.dto.SeatSelectionRequest;
 import com.thirdparty.ticketing.domain.ticket.dto.TicketElement;
 import com.thirdparty.ticketing.domain.ticket.dto.TicketPaymentRequest;
+import com.thirdparty.ticketing.domain.ticket.service.ReservationService;
 import com.thirdparty.ticketing.domain.ticket.service.TicketService;
 
 import lombok.RequiredArgsConstructor;
 
-@RestController("/api")
+@RestController
+@RequestMapping("/api")
 @RequiredArgsConstructor
 public class TicketController {
     private final TicketService ticketService;
+    private final ReservationService reservationService;
 
     @GetMapping("/members/tickets")
     public ResponseEntity<ItemResult<TicketElement>> selectMyTickets(
             @LoginMember String memberEmail) {
-        ItemResult<TicketElement> tickets = ticketService.selectMyTicket(memberEmail);
+        ItemResult<TicketElement> tickets = ItemResult.of(List.of());
+        ticketService.selectMyTicket(memberEmail);
         return ResponseEntity.ok().body(tickets);
     }
 
     @PostMapping("/seats/select")
     public ResponseEntity<Void> selectSeat(
+            @LoginMember String memberEmail,
             @RequestBody @Valid SeatSelectionRequest seatSelectionRequest) {
-        ticketService.selectSeat(seatSelectionRequest);
+        reservationService.selectSeat(memberEmail, seatSelectionRequest);
         return ResponseEntity.ok().build();
     }
 
     @PostMapping("/tickets")
-    public ResponseEntity<Void> payTicket(
+    public ResponseEntity<Void> reservationTicket(
+            @LoginMember String memberEmail,
             @RequestBody @Valid TicketPaymentRequest ticketPaymentRequest) {
-        ticketService.reservationTicket(ticketPaymentRequest);
+        reservationService.reservationTicket(memberEmail, ticketPaymentRequest);
         return ResponseEntity.ok().build();
     }
 }

src/main/java/com/thirdparty/ticketing/domain/ticket/dto/SeatSelectionRequest.java

@@ -9,5 +9,5 @@
 public class SeatSelectionRequest {
     @NotNull(message = "좌석 ID를 요청하지 않았습니다.")
     @Min(value = 1, message = "좌석 ID는 1 이상이어야 합니다.")
-    private Long seatId;
+    private final Long seatId;
 }

src/main/java/com/thirdparty/ticketing/domain/ticket/dto/TicketPaymentRequest.java

@@ -9,5 +9,5 @@
 public class TicketPaymentRequest {
     @NotNull(message = "좌석 ID를 요청하지 않았습니다.")
     @Min(value = 1, message = "좌석 ID는 1 이상이어야 합니다.")
-    private Long seatId;
+    private final Long seatId;
 }

src/main/java/com/thirdparty/ticketing/domain/ticket/service/ReservationService.java

@@ -0,0 +1,10 @@
+package com.thirdparty.ticketing.domain.ticket.service;
+
+import com.thirdparty.ticketing.domain.ticket.dto.SeatSelectionRequest;
+import com.thirdparty.ticketing.domain.ticket.dto.TicketPaymentRequest;
+
+public interface ReservationService {
+    void selectSeat(String memberEmail, SeatSelectionRequest seatSelectionRequest);
+
+    void reservationTicket(String memberEmail, TicketPaymentRequest ticketPaymentRequest);
+}