Refactor tag dto conversion

src/main/java/run/halo/app/controller/admin/api/TagController.java

@@ -1,6 +1,7 @@
 package run.halo.app.controller.admin.api;
 
 import io.swagger.annotations.ApiOperation;
+import io.swagger.annotations.ApiParam;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.web.SortDefault;
@@ -36,7 +37,9 @@ public class TagController {
     }
 
     @GetMapping
+    @ApiOperation("Lists tag")
     public List<? extends TagDTO> listTags(@SortDefault(sort = "updateTime", direction = Sort.Direction.DESC) Sort sort,
+                                           @ApiParam("Return more information(post count) if it is set")
                                            @RequestParam(name = "more", required = false, defaultValue = "false") Boolean more) {
         if (more) {
             return postTagService.listTagWithCountDtos(sort);
@@ -45,6 +48,7 @@ public class TagController {
     }
 
     @PostMapping
+    @ApiOperation("Creates tag")
     public TagDTO createTag(@Valid @RequestBody TagParam tagParam) {
         // Convert to tag
         Tag tag = tagParam.convertTo();
@@ -52,7 +56,7 @@ public class TagController {
         log.debug("Tag to be created: [{}]", tag);
 
         // Create and convert
-        return new TagDTO().convertFrom(tagService.create(tag));
+        return tagService.convertTo(tagService.create(tag));
     }
 
     /**
@@ -64,7 +68,7 @@ public class TagController {
     @GetMapping("{tagId:\\d+}")
     @ApiOperation("Get tag detail by id")
     public TagDTO getBy(@PathVariable("tagId") Integer tagId) {
-        return new TagDTO().convertFrom(tagService.getById(tagId));
+        return tagService.convertTo(tagService.getById(tagId));
     }
 
     @PutMapping("{tagId:\\d+}")
@@ -78,20 +82,17 @@ public class TagController {
         tagParam.update(tag);
 
         // Update tag
-        return new TagDTO().convertFrom(tagService.update(tag));
+        return tagService.convertTo(tagService.update(tag));
     }
 
-    /**
-     * Delete tag by id.
-     *
-     * @param tagId tag id
-     */
     @DeleteMapping("{tagId:\\d+}")
-    @ApiOperation("Delete tag by id")
+    @ApiOperation("Deletes tag")
-    public void deletePermanently(@PathVariable("tagId") Integer tagId) {
+    public TagDTO deletePermanently(@PathVariable("tagId") Integer tagId) {
         // Remove the tag
-        tagService.removeById(tagId);
+        Tag deletedTag = tagService.removeById(tagId);
         // Remove the post tag relationship
         postTagService.removeByTagId(tagId);
+
+        return tagService.convertTo(deletedTag);
     }
 }

src/main/java/run/halo/app/service/TagService.java

@@ -1,6 +1,7 @@
 package run.halo.app.service;
 
 import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
 import run.halo.app.model.dto.TagDTO;
 import run.halo.app.model.entity.Tag;
 import run.halo.app.service.base.CrudService;
@@ -25,11 +26,20 @@ public interface TagService extends CrudService<Tag, Integer> {
     Tag getBySlugNameOfNonNull(@NonNull String slugName);
 
     /**
-     * Converts to tag output dtos.
+     * Converts to tag dto.
+     *
+     * @param tag tag must not be null
+     * @return tag dto
+     */
+    @NonNull
+    TagDTO convertTo(@NonNull Tag tag);
+
+    /**
+     * Converts to tag dtos.
      *
      * @param tags tag list
      * @return a list of tag output dto
      */
     @NonNull
-    List<TagDTO> convertTo(List<Tag> tags);
+    List<TagDTO> convertTo(@Nullable List<Tag> tags);
 }

src/main/java/run/halo/app/service/impl/CategoryServiceImpl.java

@@ -177,8 +177,7 @@ public class CategoryServiceImpl extends AbstractCrudService<Category, Integer>
             return Collections.emptyList();
         }
 
-        return categories
+        return categories.stream()
-                .stream()
                 .map(this::convertTo)
                 .collect(Collectors.toList());
     }

src/main/java/run/halo/app/service/impl/TagServiceImpl.java

@@ -1,5 +1,9 @@
 package run.halo.app.service.impl;
 
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
 import run.halo.app.exception.AlreadyExistsException;
 import run.halo.app.exception.NotFoundException;
 import run.halo.app.model.dto.TagDTO;
@@ -7,9 +11,6 @@ import run.halo.app.model.entity.Tag;
 import run.halo.app.repository.TagRepository;
 import run.halo.app.service.TagService;
 import run.halo.app.service.base.AbstractCrudService;
-import lombok.extern.slf4j.Slf4j;
-import org.springframework.stereotype.Service;
-import org.springframework.util.CollectionUtils;
 
 import java.util.Collections;
 import java.util.List;
@@ -59,12 +60,21 @@ public class TagServiceImpl extends AbstractCrudService<Tag, Integer> implements
         return tagRepository.getBySlugName(slugName).orElseThrow(() -> new NotFoundException("The tag does not exist").setErrorData(slugName));
     }
 
+    @Override
+    public TagDTO convertTo(Tag tag) {
+        Assert.notNull(tag, "Tag must not be null");
+
+        return new TagDTO().convertFrom(tag);
+    }
+
     @Override
     public List<TagDTO> convertTo(List<Tag> tags) {
-        return CollectionUtils.isEmpty(tags) ?
+        if (CollectionUtils.isEmpty(tags)) {
-                Collections.emptyList() :
+            return Collections.emptyList();
-                tags.stream()
+        }
-                        .map(tag -> (TagDTO) new TagDTO().convertFrom(tag))
+
+        return tags.stream()
+                .map(this::convertTo)
                 .collect(Collectors.toList());
     }
 }