feat: Optimistic Lock to like

UMC-GREENY · Jul 11, 2024 · 9d350fe · 9d350fe
1 parent 44db52a
commit 9d350fe
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Showing 4 changed files with 39 additions and 18 deletions.
diff --git a/src/main/java/greeny/backend/domain/community/controller/PostLikeController.java b/src/main/java/greeny/backend/domain/community/controller/PostLikeController.java
@@ -32,7 +32,7 @@ public class PostLikeController {
     @ResponseStatus(OK)
     @PostMapping()
     public Response togglePostLike(Long postId) {
-        postLikeService.togglePostLike(postId, memberService.getCurrentMember());
+        postLikeService.like(postId, memberService.getCurrentMember());
         return success(SUCCESS_TO_TOGGLE_POST_LIKE);
     }
 

diff --git a/src/main/java/greeny/backend/domain/community/repository/PostLikeRepository.java b/src/main/java/greeny/backend/domain/community/repository/PostLikeRepository.java
@@ -8,6 +8,5 @@
 import java.util.Optional;
 
 public interface PostLikeRepository extends JpaRepository<PostLike, Long> {
-    @Lock(LockModeType.PESSIMISTIC_WRITE)  // 동시성 문제 방지를 위해 Pessimistic lock 사용
     Optional<PostLike> findByPostIdAndLikerId(Long postId, Long likerId);
 }
diff --git a/src/main/java/greeny/backend/domain/community/service/PostLikeService.java b/src/main/java/greeny/backend/domain/community/service/PostLikeService.java
@@ -8,37 +8,59 @@
 import greeny.backend.exception.situation.PostNotFoundException;
 import greeny.backend.exception.situation.SelfLikeNotAllowedException;
 import lombok.RequiredArgsConstructor;
+import org.springframework.dao.OptimisticLockingFailureException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
-
 import java.util.Optional;
 
 @Service
 @RequiredArgsConstructor
 public class PostLikeService {
-
     private final PostLikeRepository postLikeRepository;
-
     private final PostRepository postRepository;
 
-    // 좋아요 or 취소
-
     @Transactional
-    public void togglePostLike(Long postId, Member liker) {
-        Optional<PostLike> postLike = postLikeRepository.findByPostIdAndLikerId(postId, liker.getId());
-        // 이미 좋아요 눌렀는지 확인
-        if(postLike.isEmpty()) likePost(postId, liker); // 안 눌렀다면 좋아요 수행
-        else postLikeRepository.delete(postLike.get()); // 이미 눌렀다면 취소 수행
-
+    public void like(Long postId, Member liker) {
+        boolean retry;
+        do {
+            try {
+                retry = false;
+                Optional<PostLike> foundPostLike = findPostLike(postId, liker.getId());
+                toggle(postId, liker, foundPostLike);
+            }
+            catch (OptimisticLockingFailureException e) {
+                retry = true;
+            }
+        } while (retry);
     }
 
-    // 게시글 좋아요
-    public void likePost(Long postId, Member liker){
-        Post post = postRepository.findByIdWithWriter(postId).orElseThrow(PostNotFoundException::new);
-        if(post.getWriter().getId().equals(liker.getId())) throw new SelfLikeNotAllowedException(); // 자기의 게시글에는 좋아요를 누를 수 없음
+    public void create(Long postId, Member liker) {
+        Post post = getPost(postId);
+        if (post.getWriter().getId().equals(liker.getId()))
+            throw new SelfLikeNotAllowedException();
         postLikeRepository.save(PostLike.builder()
                 .post(post)
                 .liker(liker)
                 .build());
     }
+
+    public Post getPost(Long postId) {
+        return postRepository.findByIdWithWriter(postId).orElseThrow(PostNotFoundException::new);
+    }
+
+    public Optional<PostLike> findPostLike(Long postId, Long likerId) {
+        return postLikeRepository.findByPostIdAndLikerId(postId, likerId);
+    }
+
+    private void delete(PostLike postLike) {
+        postLikeRepository.delete(postLike);
+    }
+
+    private void toggle(Long postId, Member liker, Optional<PostLike> postLike) {
+        if (postLike.isEmpty()) {
+            create(postId, liker);
+            return;
+        }
+        delete(postLike.get());
+    }
 }
diff --git a/src/main/java/greeny/backend/domain/community/service/PostService.java b/src/main/java/greeny/backend/domain/community/service/PostService.java
@@ -124,7 +124,7 @@ public void editPostInfo(Long postId, WritePostRequestDto editPostInfoRequestDto
     }
 
     @Transactional
-    protected void uploadPostFileList(List<MultipartFile> multipartFiles, Post post) {
+    public void uploadPostFileList(List<MultipartFile> multipartFiles, Post post) {
         // s3에 파일을 업로드 한 뒤 예외가 발생하면 db는 롤백이 되지만,
         // 이미 s3에 저장된 이미지는 삭제되지 않는 문제가 있음.