feat: 레이팅 조회 쿼리 개선

src/main/kotlin/com/yourssu/soongpt/domain/rating/implement/RatingReader.kt

@@ -1,42 +1,14 @@
 package com.yourssu.soongpt.domain.rating.implement
 
 import com.yourssu.soongpt.domain.course.implement.Courses
-import com.yourssu.soongpt.domain.rating.implement.Rating.Companion.INIT
-import com.yourssu.soongpt.domain.rating.implement.exception.RatingNotFoundByCourseNameException
 import org.springframework.stereotype.Component
 
 @Component
 class RatingReader(
     private val ratingRepository: RatingRepository,
 ) {
     fun findAllPointPairs(courses: Courses): Map<Long, Double> {
-        val ratings = findAllBy(courses)
-        val pointPairs = mutableMapOf<Long, Double>()
-        for (course in courses.values) {
-            val find = ratings.find {
-                it.courseName == course.courseName && it.professorName == course.professorName
-            }
-            pointPairs[course.id!!] = find?.point ?: INIT
-        }
-        return pointPairs
-    }
-
-    private fun findAllBy(courses: Courses): List<Rating> {
-        val ratings = mutableListOf<Rating>()
-        for (course in courses.values) {
-            val rating = ratingRepository.findByCourseNameAndProfessorName(
-                course.courseName,
-                course.professorName?: ""
-            )
-            if (rating != null) {
-                ratings.add(rating)
-            }
-        }
-        return ratings
-    }
-
-    fun findBy(courseName: String, professorName: String): Rating {
-        return ratingRepository.findByCourseNameAndProfessorName(courseName, professorName)
-            ?: throw RatingNotFoundByCourseNameException()
+        val candidates = courses.values.map { Triple(it.id!!, it.courseName, it.professorName?:"") }
+        return ratingRepository.findAllByCourseNameAndProfessorName(candidates)
     }
 }

src/main/kotlin/com/yourssu/soongpt/domain/rating/implement/RatingRepository.kt

@@ -3,4 +3,5 @@ package com.yourssu.soongpt.domain.rating.implement
 interface RatingRepository {
     fun save(rating: Rating): Rating
     fun findByCourseNameAndProfessorName(courseName: String, professorName: String): Rating?
+    fun findAllByCourseNameAndProfessorName(pairs: List<Triple<Long, String, String>>): Map<Long, Double>
 }

src/main/kotlin/com/yourssu/soongpt/domain/rating/storage/RatingRepositoryImpl.kt

@@ -18,12 +18,34 @@ class RatingRepositoryImpl(
 
     override fun findByCourseNameAndProfessorName(courseName: String, professorName: String): Rating? {
         return jpaQueryFactory.selectFrom(ratingEntity)
-            .where(ratingEntity.courseName.like(courseName))
+            .where(ratingEntity.courseName.eq(courseName))
             .where(ratingEntity.professorName.eq(professorName))
             .fetchFirst()
             ?.toDomain()
     }
+
+    override fun findAllByCourseNameAndProfessorName(pairs: List<Triple<Long, String, String>>): Map<Long, Double> {
+        val results = mutableMapOf<Long, Double>()
+
+        val predicates = pairs.map {
+            ratingEntity.courseName.eq(it.second).and(ratingEntity.professorName.eq(it.third))
+        }
+
+        val ratings = jpaQueryFactory.selectFrom(ratingEntity)
+            .where(predicates.reduce { acc, predicate -> acc.or(predicate) })
+            .fetch()
+            .map { it.toDomain() }
+
+        for (pair in pairs) {
+            val rating =
+                ratings.find { it.courseName == pair.second && it.professorName == pair.third }
+            results[pair.first] = rating?.point ?: Rating.INIT
+        }
+        return results
+    }
+
+
 }
 
-interface RatingJpaRepository: JpaRepository<RatingEntity, Long> {
+interface RatingJpaRepository : JpaRepository<RatingEntity, Long> {
 }