카테고리 관련 기능 구현 (#8)

BACK/spring-app/src/main/java/com/starchive/springapp/category/controller/CategoryController.java

@@ -1,17 +1,25 @@
 package com.starchive.springapp.category.controller;
 
+import com.starchive.springapp.category.dto.CategoryCreateRequest;
 import com.starchive.springapp.category.dto.CategoryDto;
+import com.starchive.springapp.category.dto.CategoryUpdateRequest;
+import com.starchive.springapp.category.dto.CategoryUpdateResponse;
 import com.starchive.springapp.category.service.CategoryService;
 import com.starchive.springapp.global.dto.ResponseDto;
 import com.starchive.springapp.hashtag.dto.HashTagDto;
 import com.starchive.springapp.hashtag.service.HashTagService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.Null;
 import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
@@ -36,4 +44,28 @@ public ResponseEntity<ResponseDto<List<HashTagDto>>> showHashTags(@PathVariable(
         ResponseDto<List<HashTagDto>> listResponseDto = new ResponseDto<>(categories);
         return ResponseEntity.ok(listResponseDto);
     }
+
+    @PostMapping("/categories")
+    @Operation(summary = "카테고리 생성")
+    public ResponseEntity<Null> createCategory(@Valid CategoryCreateRequest categoryCreateRequest) {
+        categoryService.create(categoryCreateRequest);
+
+        return ResponseEntity.noContent().build();
+    }
+
+    @PutMapping("/categories")
+    @Operation(summary = "카테고리 수정")
+    public ResponseEntity<ResponseDto<CategoryUpdateResponse>> updateCategory(
+            @Valid CategoryUpdateRequest categoryUpdateRequest) {
+        CategoryUpdateResponse updateResponse = categoryService.update(categoryUpdateRequest);
+
+        return ResponseEntity.ok(new ResponseDto<>(updateResponse));
+    }
+
+    @DeleteMapping("/categories/{categoryId}")
+    @Operation(summary = "카테고리 삭제")
+    public ResponseEntity<Null> deleteCategory(@PathVariable("categoryId") Long categoryId) {
+        categoryService.delete(categoryId);
+        return ResponseEntity.noContent().build();
+    }
 }

BACK/spring-app/src/main/java/com/starchive/springapp/category/domain/Category.java

@@ -2,6 +2,7 @@
 
 import static jakarta.persistence.FetchType.LAZY;
 
+import jakarta.persistence.CascadeType;
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
@@ -33,7 +34,7 @@ public class Category {
     @Column(length = 100)
     String name;
 
-    @OneToMany(mappedBy = "parent", fetch = LAZY)
+    @OneToMany(mappedBy = "parent", fetch = LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
     private List<Category> children = new ArrayList<>();
 
     public Category(String name, Category parent) {
@@ -44,9 +45,15 @@ public Category(String name, Category parent) {
         }
     }
 
-    private void changeParent(Category parent) {
+    public void changeName(String name) {
+        this.name = name;
+    }
+
+    public void changeParent(Category parent) {
         this.parent = parent;
-        parent.getChildren().add(this);
+        if (parent != null) {
+            parent.getChildren().add(this);
+        }
     }
 
 }

BACK/spring-app/src/main/java/com/starchive/springapp/category/dto/CategoryCreateRequest.java

@@ -0,0 +1,20 @@
+package com.starchive.springapp.category.dto;
+
+import jakarta.annotation.Nullable;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class CategoryCreateRequest {
+    @Size(max = 100)
+    @NotNull
+    private String name;
+
+    @Nullable
+    private Long parentId;
+}

BACK/spring-app/src/main/java/com/starchive/springapp/category/dto/CategoryUpdateRequest.java

@@ -0,0 +1,23 @@
+package com.starchive.springapp.category.dto;
+
+import jakarta.annotation.Nullable;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.Size;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class CategoryUpdateRequest {
+    @NotNull
+    private Long categoryId;
+
+    @Size(max = 100)
+    @NotNull
+    private String name;
+
+    @Nullable
+    private Long parentId;
+}

BACK/spring-app/src/main/java/com/starchive/springapp/category/dto/CategoryUpdateResponse.java

@@ -0,0 +1,29 @@
+package com.starchive.springapp.category.dto;
+
+import com.starchive.springapp.category.domain.Category;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class CategoryUpdateResponse {
+    private Long categoryId;
+
+    private String name;
+
+    private Long parentId;
+
+    public static CategoryUpdateResponse from(Category category) {
+        CategoryUpdateResponse categoryUpdateResponse = new CategoryUpdateResponse();
+        categoryUpdateResponse.categoryId = category.getId();
+        categoryUpdateResponse.name = category.getName();
+        if (category.getParent() == null) {
+            categoryUpdateResponse.parentId = null;
+        } else {
+            categoryUpdateResponse.parentId = category.getParent().getId();
+        }
+        return categoryUpdateResponse;
+    }
+}

BACK/spring-app/src/main/java/com/starchive/springapp/category/exception/CategoryAlreadyExistsException.java

@@ -0,0 +1,26 @@
+package com.starchive.springapp.category.exception;
+
+import static com.starchive.springapp.global.ErrorMessage.ALREADY_EXISTS_CATEGORY;
+
+public class CategoryAlreadyExistsException extends RuntimeException {
+    public CategoryAlreadyExistsException() {
+        super(ALREADY_EXISTS_CATEGORY);
+    }
+
+    public CategoryAlreadyExistsException(String message) {
+        super(message);
+    }
+
+    public CategoryAlreadyExistsException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public CategoryAlreadyExistsException(Throwable cause) {
+        super(cause);
+    }
+
+    protected CategoryAlreadyExistsException(String message, Throwable cause, boolean enableSuppression,
+                                             boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}

BACK/spring-app/src/main/java/com/starchive/springapp/category/repository/CategoryRepository.java

@@ -9,8 +9,14 @@
 
 public interface CategoryRepository extends JpaRepository<Category, Long> {
     @Query("SELECT c FROM Category c LEFT JOIN FETCH c.children left join fetch c.parent WHERE c.id = :id")
-    Optional<Category> findByIdWithChildren(@Param("id") Long id);
+    Optional<Category> findByIdWithParentAndChildren(@Param("id") Long id);
 
     @Query("SELECT DISTINCT c FROM Category c LEFT JOIN FETCH c.children WHERE c.parent IS NULL")
     List<Category> findRootCategoriesWithChildren();
+
+    Optional<Category> findByName(@Param("name") String name);
+
+    @Query("select c from Category c left join fetch c.parent where c.id = :id")
+    Optional<Category> findByIdWithParent(@Param("id") Long id);
+
 }

BACK/spring-app/src/main/java/com/starchive/springapp/category/service/CategoryService.java

@@ -1,26 +1,126 @@
 package com.starchive.springapp.category.service;
 
 import com.starchive.springapp.category.domain.Category;
+import com.starchive.springapp.category.dto.CategoryCreateRequest;
 import com.starchive.springapp.category.dto.CategoryDto;
+import com.starchive.springapp.category.dto.CategoryUpdateRequest;
+import com.starchive.springapp.category.dto.CategoryUpdateResponse;
+import com.starchive.springapp.category.exception.CategoryAlreadyExistsException;
 import com.starchive.springapp.category.exception.CategoryNotFoundException;
 import com.starchive.springapp.category.repository.CategoryRepository;
+import com.starchive.springapp.post.repository.PostRepository;
+import java.util.ArrayList;
 import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 @Service
+@Transactional
 @RequiredArgsConstructor
 public class CategoryService {
     private final CategoryRepository categoryRepository;
+    private final PostRepository postRepository;
 
     public List<CategoryDto> findAll() {
         List<Category> rootCateGories = categoryRepository.findRootCategoriesWithChildren();
         return rootCateGories.stream().map(CategoryDto::from).toList();
     }
 
     public Category findOne(Long id) {
-        return categoryRepository.findByIdWithChildren(id).orElseThrow(CategoryNotFoundException::new);
+        return categoryRepository.findByIdWithParentAndChildren(id).orElseThrow(CategoryNotFoundException::new);
     }
 
 
+    public void create(CategoryCreateRequest categoryCreateRequest) {
+        categoryRepository.findByName(categoryCreateRequest.getName()).ifPresent(category -> {
+            throw new CategoryAlreadyExistsException();
+        });
+
+        if (categoryCreateRequest.getParentId() == null) {
+            Category category = new Category(categoryCreateRequest.getName(), null);
+            categoryRepository.save(category);
+            return;
+        }
+
+        Category parentCategory = categoryRepository.findById(categoryCreateRequest.getParentId())
+                .orElseThrow(() -> new CategoryNotFoundException("존재하지 않는 부모 카테고리입니다."));
+
+        Category category = new Category(categoryCreateRequest.getName(), parentCategory);
+        categoryRepository.save(category);
+
+    }
+
+    public CategoryUpdateResponse update(CategoryUpdateRequest categoryUpdateRequest) {
+        Category category = categoryRepository.findByIdWithParent(categoryUpdateRequest.getCategoryId())
+                .orElseThrow(CategoryNotFoundException::new);
+
+        if (!category.getName().equals(categoryUpdateRequest.getName())) {
+            categoryRepository.findByName(categoryUpdateRequest.getName()).ifPresent(findOne -> {
+                throw new CategoryAlreadyExistsException(categoryUpdateRequest.getName() + " 은 이미 존재하는 카테고리 이름입니다.");
+            });
+
+            category.changeName(categoryUpdateRequest.getName());
+        }
+
+        updateParentCategory(categoryUpdateRequest, category);
+
+        return CategoryUpdateResponse.from(category);
+    }
+
+    public void delete(Long id) {
+        if (id == 0) {
+            throw new RuntimeException("삭제할 수 없는 카테고리입니다.");
+        }
+        Category category = categoryRepository.findByIdWithParentAndChildren(id)
+                .orElseThrow(CategoryNotFoundException::new);
+
+        List<Long> categoryIds = new ArrayList<>();
+        categoryIds.add(category.getId());
+
+        if (!category.getChildren().isEmpty()) {
+            for (Category child : category.getChildren()) {
+                categoryIds.add(child.getId());
+            }
+        }
+
+        postRepository.bulkUpdateToNoneCategory(categoryIds);
+
+        categoryRepository.deleteById(category.getId());
+    }
+
+    private Category updateParentCategory(CategoryUpdateRequest categoryUpdateRequest, Category category) {
+        Long newParentId = categoryUpdateRequest.getParentId();
+        if (category.getParent() != null && newParentId == null) {
+            category.changeParent(null);
+            return category;
+        }
+
+        if (category.getParent() != null && newParentId != null) {
+
+            Category parentCategory = findParentCategoryById(newParentId);
+
+            if (category.getParent().getId() != newParentId) {
+                category.changeParent(parentCategory);
+            }
+
+            return category;
+        }
+
+        if (category.getParent() == null && newParentId != null) {
+
+            Category parentCategory = findParentCategoryById(newParentId);
+
+            category.changeParent(parentCategory);
+
+            return category;
+        }
+
+        return category;
+    }
+
+    private Category findParentCategoryById(Long parentId) {
+        return categoryRepository.findById(parentId)
+                .orElseThrow(() -> new CategoryNotFoundException("존재하지 않는 부모 카테고리입니다."));
+    }
 }

BACK/spring-app/src/main/java/com/starchive/springapp/global/ErrorMessage.java

@@ -7,4 +7,5 @@ public class ErrorMessage {
     final public static String CATEGORY_NOT_FOUND = "카테고리가 존재하지 않습니다.";
     final public static String HASHTAG_NOT_FOUND = "해쉬태그가 존재하지 않습니다.";
     final public static String POST_NOT_FOUND = "게시글이 존재하지 않습니다.";
+    final public static String ALREADY_EXISTS_CATEGORY = "이미 존재하는 카테고리 이름입니다.";
 }

BACK/spring-app/src/main/java/com/starchive/springapp/global/dto/ErrorResult.java

@@ -0,0 +1,12 @@
+package com.starchive.springapp.global.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import org.springframework.http.HttpStatus;
+
+@Data
+@AllArgsConstructor
+public class ErrorResult {
+    private HttpStatus code;
+    private String message;
+}