From 999b8ed4374ef878193ac786b9b15cbf5f2d0232 Mon Sep 17 00:00:00 2001
From: Hunor Tot-Bagi <hunortotbagi@gmail.com>
Date: Fri, 20 Sep 2024 22:04:55 +0300
Subject: [PATCH] Fix: Delete `Subject` (#113)

* fix: path variable typo

* feat: add FetchType.EAGER

* feat: remove all students and teachers before deleting
---
 .../com/electric_diary/controllers/SubjectController.java  | 4 ++--
 .../java/com/electric_diary/entities/SubjectEntity.java    | 7 ++++---
 .../electric_diary/services/impl/SubjectServiceImpl.java   | 7 +++++++
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/electric_diary/controllers/SubjectController.java b/src/main/java/com/electric_diary/controllers/SubjectController.java
index 5d4ef8c..6b6c222 100644
--- a/src/main/java/com/electric_diary/controllers/SubjectController.java
+++ b/src/main/java/com/electric_diary/controllers/SubjectController.java
@@ -45,8 +45,8 @@ public ResponseEntity<SubjectEntity> updateSubject(@PathVariable Integer subject
 	}
 
 	@DeleteMapping("/{subjectId}")
-	public ResponseEntity<SubjectEntity> deleteSubject(@PathVariable Integer subjectid) {
-		return new ResponseEntity<>(subjectService.deleteSubject(subjectid), HttpStatus.OK);
+	public ResponseEntity<SubjectEntity> deleteSubject(@PathVariable Integer subjectId) {
+		return new ResponseEntity<>(subjectService.deleteSubject(subjectId), HttpStatus.OK);
 	}
 
 	@PutMapping("/{subjectId}/students/{studentId}")
diff --git a/src/main/java/com/electric_diary/entities/SubjectEntity.java b/src/main/java/com/electric_diary/entities/SubjectEntity.java
index 5646ded..6701d77 100644
--- a/src/main/java/com/electric_diary/entities/SubjectEntity.java
+++ b/src/main/java/com/electric_diary/entities/SubjectEntity.java
@@ -6,6 +6,7 @@
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
 import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
@@ -35,14 +36,14 @@ public class SubjectEntity {
 
 	@NotNull
 	@JsonIgnore
-	@OneToMany(mappedBy = "subject")
+	@OneToMany(mappedBy = "subject", fetch = FetchType.EAGER)
 	private Set<GradeEntity> grades = new HashSet<GradeEntity>();
 
-	@ManyToMany
+	@ManyToMany(fetch = FetchType.EAGER)
 	@JoinTable(name = "student_enrolled", joinColumns = @JoinColumn(name = "subject_id"), inverseJoinColumns = @JoinColumn(name = "student_id"))
 	private Set<StudentEntity> enrolledStudents = new HashSet<>();
 
-	@ManyToMany(mappedBy = "subjects")
+	@ManyToMany(mappedBy = "subjects", fetch = FetchType.EAGER)
 	private Set<TeacherEntity> teachers = new HashSet<>();
 
 	public void enrolStudents(StudentEntity student) {
diff --git a/src/main/java/com/electric_diary/services/impl/SubjectServiceImpl.java b/src/main/java/com/electric_diary/services/impl/SubjectServiceImpl.java
index ff91e9c..8f6d078 100644
--- a/src/main/java/com/electric_diary/services/impl/SubjectServiceImpl.java
+++ b/src/main/java/com/electric_diary/services/impl/SubjectServiceImpl.java
@@ -7,6 +7,7 @@
 import com.electric_diary.DTO.Request.SubjectRequestDTO;
 import com.electric_diary.entities.StudentEntity;
 import com.electric_diary.entities.SubjectEntity;
+import com.electric_diary.entities.TeacherEntity;
 import com.electric_diary.exception.NotFoundException;
 import com.electric_diary.repositories.StudentRepository;
 import com.electric_diary.repositories.SubjectRepository;
@@ -68,6 +69,12 @@ public SubjectEntity updateSubject(Integer subjectId, SubjectRequestDTO subjectR
 	@Override
 	public SubjectEntity deleteSubject(Integer subjectId) {
 		SubjectEntity subject = getSubjectById(subjectId);
+		for (StudentEntity student : subject.getEnrolledStudents())
+			student.getSubjects().remove(subject);
+
+		for (TeacherEntity teacher : subject.getTeachers())
+			teacher.getSubjects().remove(subject);
+
 		subjectRepository.delete(subject);
 		logger.info("Deleted subject with ID {}.", subjectId);
 		return subject;