Features/cursor pagination

src/main/kotlin/com/solve/domain/post/controller/PostCommentController.kt

@@ -19,9 +19,9 @@ class PostCommentController(
     @GetMapping
     fun getComments(
         @PathVariable postId: Long,
-        @RequestParam(required = false, defaultValue = "0") page: Int,
+        @RequestParam(required = false) cursorId: Long?,
         @RequestParam(required = false, defaultValue = "10") size: Int
-    ) = BaseResponse.of(postCommentService.getComments(postId, PageRequest.of(page, size)))
+    ) = BaseResponse.of(postCommentService.getComments(postId, cursorId, size))
 
     @Operation(summary = "게시글 댓글 생성")
     @PostMapping

src/main/kotlin/com/solve/domain/post/controller/PostCommentReplyController.kt

@@ -6,7 +6,6 @@ import com.solve.domain.post.service.PostCommentReplyService
 import com.solve.global.common.dto.BaseResponse
 import io.swagger.v3.oas.annotations.Operation
 import io.swagger.v3.oas.annotations.tags.Tag
-import org.springframework.data.domain.PageRequest
 import org.springframework.web.bind.annotation.DeleteMapping
 import org.springframework.web.bind.annotation.GetMapping
 import org.springframework.web.bind.annotation.PatchMapping
@@ -28,9 +27,9 @@ class PostCommentReplyController(
     fun getReplies(
         @PathVariable postId: Long,
         @PathVariable commentId: Long,
-        @RequestParam(required = false, defaultValue = "0") page: Int,
+        @RequestParam(required = false) cursorId: Long?,
         @RequestParam(required = false, defaultValue = "10") size: Int
-    ) = BaseResponse.of(postCommentReplyService.getReplies(postId, commentId, PageRequest.of(page, size)))
+    ) = BaseResponse.of(postCommentReplyService.getReplies(postId, commentId, cursorId, size))
 
     @Operation(summary = "게시글 댓글 답글 생성")
     @PostMapping

src/main/kotlin/com/solve/domain/post/error/PostCommentError.kt

@@ -5,5 +5,6 @@ import org.springframework.http.HttpStatus
 
 enum class PostCommentError(override val status: HttpStatus, override val message: String) : CustomError {
     POST_COMMENT_NOT_FOUND(HttpStatus.NOT_FOUND, "게시글 댓글을 찾을 수 없습니다. (id: %s)"),
-    POST_COMMENT_NOT_AUTHORIZED(HttpStatus.FORBIDDEN, "게시글 댓글에 권한이 없습니다. (id: %s)")
+    POST_COMMENT_NOT_AUTHORIZED(HttpStatus.FORBIDDEN, "게시글 댓글에 권한이 없습니다. (id: %s)"),
+    POST_COMMENT_CURSOR_NOT_FOUND(HttpStatus.NOT_FOUND, "게시글 댓글을 찾을 수 없습니다. (cursor: %s)"),
 }

src/main/kotlin/com/solve/domain/post/error/PostCommentReplyError.kt

@@ -5,5 +5,6 @@ import org.springframework.http.HttpStatus
 
 enum class PostCommentReplyError(override val status: HttpStatus, override val message: String): CustomError {
     POST_COMMENT_REPLY_NOT_FOUND(HttpStatus.NOT_FOUND, "댓글 답글을 찾을 수 없습니다. (id: %s)"),
-    POST_COMMENT_REPLY_NOT_AUTHORIZED(HttpStatus.FORBIDDEN, "댓글 답글 권한이 없습니다.")
+    POST_COMMENT_REPLY_NOT_AUTHORIZED(HttpStatus.FORBIDDEN, "댓글 답글 권한이 없습니다."),
+    POST_COMMENT_REPLY_CURSOR_NOT_FOUND(HttpStatus.NOT_FOUND, "댓글 답글 커서를 찾을 수 없습니다. (id: %s)")
 }

src/main/kotlin/com/solve/domain/post/repository/PostCommentQueryRepository.kt

@@ -2,9 +2,7 @@ package com.solve.domain.post.repository
 
 import com.solve.domain.post.domain.entity.Post
 import com.solve.domain.post.domain.entity.PostComment
-import org.springframework.data.domain.Page
-import org.springframework.data.domain.Pageable
 
 interface PostCommentQueryRepository {
-    fun getComments(post: Post, pageable: Pageable): Page<PostComment>
+    fun getComments(post: Post, cursor: PostComment?, size: Int): List<PostComment>
 }

src/main/kotlin/com/solve/domain/post/repository/PostCommentReplyQueryRepository'.kt → src/main/kotlin/com/solve/domain/post/repository/PostCommentReplyQueryRepository.kt

@@ -3,9 +3,7 @@ package com.solve.domain.post.repository
 import com.solve.domain.post.domain.entity.Post
 import com.solve.domain.post.domain.entity.PostComment
 import com.solve.domain.post.domain.entity.PostCommentReply
-import org.springframework.data.domain.Page
-import org.springframework.data.domain.Pageable
 
 interface PostCommentReplyQueryRepository {
-    fun getReplies(post: Post, comment: PostComment, pageable: Pageable): Page<PostCommentReply>
+    fun getReplies(post: Post, comment: PostComment, cursor: PostCommentReply?, size: Int): List<PostCommentReply>
 }

src/main/kotlin/com/solve/domain/post/repository/impl/PostCommentQueryRepositoryImpl.kt

@@ -1,13 +1,11 @@
 package com.solve.domain.post.repository.impl
 
+import com.querydsl.core.types.dsl.BooleanExpression
 import com.querydsl.jpa.impl.JPAQueryFactory
 import com.solve.domain.post.domain.entity.Post
 import com.solve.domain.post.domain.entity.PostComment
 import com.solve.domain.post.domain.entity.QPostComment
 import com.solve.domain.post.repository.PostCommentQueryRepository
-import org.springframework.data.domain.Page
-import org.springframework.data.domain.PageImpl
-import org.springframework.data.domain.Pageable
 import org.springframework.stereotype.Repository
 import org.springframework.transaction.annotation.Transactional
 
@@ -18,21 +16,27 @@ class PostCommentQueryRepositoryImpl(
     private val postComment = QPostComment.postComment
 
     @Transactional(readOnly = true)
-    override fun getComments(post: Post, pageable: Pageable): Page<PostComment> {
-        val baseQuery = queryFactory
+    override fun getComments(
+        post: Post,
+        cursor: PostComment?,
+        size: Int
+    ): List<PostComment> {
+        return queryFactory
             .selectFrom(postComment)
-            .where(postComment.post.eq(post))
-            .offset(pageable.offset)
-            .limit(pageable.pageSize.toLong())
-            .orderBy(postComment._createdAt.desc())
-
-        val comments = baseQuery.fetch()
-        val totalCount = queryFactory
-            .select(postComment.count())
-            .from(postComment)
-            .where(postComment.post.eq(post))
-            .fetchOne() ?: 0L
+            .where(
+                postComment.post.eq(post),
+                cursorIdCondition(cursor)
+            )
+            .orderBy(postComment._createdAt.desc(), postComment.id.desc())
+            .limit(size.toLong())
+            .fetch() ?: emptyList()
+    }
 
-        return PageImpl(comments, pageable, totalCount)
+    private fun cursorIdCondition(cursor: PostComment?): BooleanExpression? {
+        return if (cursor != null) {
+            postComment.id.lt(cursor.id!!)
+        } else {
+            null
+        }
     }
 }

src/main/kotlin/com/solve/domain/post/repository/impl/PostCommentReplyQueryRepositoryImpl.kt

@@ -1,14 +1,12 @@
 package com.solve.domain.post.repository.impl
 
+import com.querydsl.core.types.dsl.BooleanExpression
 import com.querydsl.jpa.impl.JPAQueryFactory
 import com.solve.domain.post.domain.entity.Post
 import com.solve.domain.post.domain.entity.PostComment
 import com.solve.domain.post.domain.entity.PostCommentReply
 import com.solve.domain.post.domain.entity.QPostCommentReply
 import com.solve.domain.post.repository.PostCommentReplyQueryRepository
-import org.springframework.data.domain.Page
-import org.springframework.data.domain.PageImpl
-import org.springframework.data.domain.Pageable
 import org.springframework.stereotype.Repository
 import org.springframework.transaction.annotation.Transactional
 
@@ -19,27 +17,29 @@ class PostCommentReplyQueryRepositoryImpl(
     private val reply = QPostCommentReply.postCommentReply
 
     @Transactional(readOnly = true)
-    override fun getReplies(post: Post, comment: PostComment, pageable: Pageable): Page<PostCommentReply> {
-        val baseQuery = queryFactory
+    override fun getReplies(
+        post: Post,
+        comment: PostComment,
+        cursor: PostCommentReply?,
+        size: Int
+    ): List<PostCommentReply> {
+        return queryFactory
             .selectFrom(reply)
             .where(
                 reply.post.eq(post),
-                reply.comment.eq(comment)
+                reply.comment.eq(comment),
+                cursorIdCondition(cursor)
             )
-            .offset(pageable.offset)
-            .limit(pageable.pageSize.toLong())
             .orderBy(reply._createdAt.asc())
+            .limit(size.toLong())
+            .fetch() ?: emptyList()
+    }
 
-        val replies = baseQuery.fetch()
-        val totalCount = queryFactory
-            .select(reply.count())
-            .from(reply)
-            .where(
-                reply.post.eq(post),
-                reply.comment.eq(comment)
-            )
-            .fetchOne() ?: 0L
-
-        return PageImpl(replies, pageable, totalCount)
+    private fun cursorIdCondition(cursor: PostCommentReply?): BooleanExpression? {
+        return if (cursor != null) {
+            reply.id.gt(cursor.id)
+        } else {
+            null
+        }
     }
 }

src/main/kotlin/com/solve/domain/post/service/PostCommentReplyService.kt

@@ -3,11 +3,9 @@ package com.solve.domain.post.service
 import com.solve.domain.post.dto.request.PostCommentReplyCreateRequest
 import com.solve.domain.post.dto.request.PostCommentReplyUpdateRequest
 import com.solve.domain.post.dto.response.PostCommentReplyResponse
-import org.springframework.data.domain.Page
-import org.springframework.data.domain.Pageable
 
 interface PostCommentReplyService {
-    fun getReplies(postId: Long, commentId: Long, pageable: Pageable): Page<PostCommentReplyResponse>
+    fun getReplies(postId: Long, commentId: Long, cursorId: Long?, size: Int): List<PostCommentReplyResponse>
     fun createReply(postId: Long, commentId: Long, request: PostCommentReplyCreateRequest)
     fun updateReply(postId: Long, commentId: Long, replyId: Long, request: PostCommentReplyUpdateRequest)
     fun deleteReply(postId: Long, commentId: Long, replyId: Long)

src/main/kotlin/com/solve/domain/post/service/PostCommentService.kt

@@ -7,7 +7,7 @@ import org.springframework.data.domain.Page
 import org.springframework.data.domain.Pageable
 
 interface PostCommentService {
-    fun getComments(postId: Long, pageable: Pageable): Page<PostCommentResponse>
+    fun getComments(postId: Long, cursorId: Long?, size: Int): List<PostCommentResponse>
     fun createComment(postId: Long, request: PostCommentCreateRequest)
     fun updateComment(postId: Long, commentId: Long, request: PostCommentUpdateRequest)
     fun deleteComment(postId: Long, commentId: Long)

src/main/kotlin/com/solve/domain/post/service/impl/PostCommentReplyServiceImpl.kt

@@ -12,8 +12,6 @@ import com.solve.domain.post.repository.*
 import com.solve.domain.post.service.PostCommentReplyService
 import com.solve.global.error.CustomException
 import com.solve.global.security.holder.SecurityHolder
-import org.springframework.data.domain.Page
-import org.springframework.data.domain.Pageable
 import org.springframework.data.repository.findByIdOrNull
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
@@ -28,10 +26,11 @@ class PostCommentReplyServiceImpl(
     private val postCommentReplyQueryRepository: PostCommentReplyQueryRepository
 ) : PostCommentReplyService {
     @Transactional(readOnly = true)
-    override fun getReplies(postId: Long, commentId: Long, pageable: Pageable): Page<PostCommentReplyResponse> {
+    override fun getReplies(postId: Long, commentId: Long, cursorId: Long?, size: Int): List<PostCommentReplyResponse> {
         val post = postRepository.findByIdOrNull(postId) ?: throw CustomException(PostError.POST_NOT_FOUND)
         val comment = postCommentRepository.findByPostAndId(post, commentId) ?: throw CustomException(PostCommentError.POST_COMMENT_NOT_FOUND)
-        val replies = postCommentReplyQueryRepository.getReplies(post, comment, pageable)
+        val cursor = cursorId?.let { postCommentReplyRepository.findByIdOrNull(it) ?: throw CustomException(PostCommentReplyError.POST_COMMENT_REPLY_CURSOR_NOT_FOUND) }
+        val replies = postCommentReplyQueryRepository.getReplies(post, comment, cursor, size)
 
         return replies.map { it.toResponse() }
     }

src/main/kotlin/com/solve/domain/post/service/impl/PostCommentServiceImpl.kt

@@ -11,8 +11,6 @@ import com.solve.domain.post.repository.*
 import com.solve.domain.post.service.PostCommentService
 import com.solve.global.error.CustomException
 import com.solve.global.security.holder.SecurityHolder
-import org.springframework.data.domain.Page
-import org.springframework.data.domain.Pageable
 import org.springframework.data.repository.findByIdOrNull
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
@@ -27,9 +25,10 @@ class PostCommentServiceImpl(
     private val postCommentReplyRepository: PostCommentReplyRepository,
 ) : PostCommentService {
     @Transactional(readOnly = true)
-    override fun getComments(postId: Long, pageable: Pageable): Page<PostCommentResponse> {
+    override fun getComments(postId: Long, cursorId: Long?, size: Int): List<PostCommentResponse> {
         val post = postRepository.findByIdOrNull(postId) ?: throw CustomException(PostError.POST_NOT_FOUND, postId)
-        val comments = postCommentQueryRepository.getComments(post, pageable)
+        val cursor = cursorId?.let { postCommentRepository.findByIdOrNull(it) ?: throw CustomException(PostCommentError.POST_COMMENT_CURSOR_NOT_FOUND, it) }
+        val comments = postCommentQueryRepository.getComments(post, cursor, size)
 
         return comments.map { it.toResponse() }
     }