Fix tag count fetch feature

src/main/java/cc/ryanc/halo/model/projection/TagPostCountProjection.java

@@ -0,0 +1,28 @@
+package cc.ryanc.halo.model.projection;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+/**
+ * Tag post count projection.
+ *
+ * @author johnniang
+ * @date 3/26/19
+ */
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class TagPostCountProjection {
+
+    /**
+     * Post count.
+     */
+    private Long count;
+
+    /**
+     * Tag id
+     */
+    private Integer tagId;
+
+}

src/main/java/cc/ryanc/halo/repository/PostTagRepository.java

@@ -1,6 +1,7 @@
 package cc.ryanc.halo.repository;
 
 import cc.ryanc.halo.model.entity.PostTag;
+import cc.ryanc.halo.model.projection.TagPostCountProjection;
 import cc.ryanc.halo.repository.base.BaseRepository;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.lang.NonNull;
@@ -80,4 +81,23 @@ public interface PostTagRepository extends BaseRepository<PostTag, Integer> {
      */
     @NonNull
     List<PostTag> deleteByTagId(@NonNull Integer tagId);
+
+    /**
+     * Finds post count by tag id collection.
+     *
+     * @param tagIds tag id collection must not be null
+     * @return a list of tag post count projection
+     */
+    @Query("select new cc.ryanc.halo.model.projection.TagPostCountProjection(count(pt.postId), pt.tagId) from PostTag pt where pt.tagId in ?1 group by pt.tagId")
+    @NonNull
+    List<TagPostCountProjection> findPostCountByTagIds(@NonNull Iterable<Integer> tagIds);
+
+    /**
+     * Finds post count of tag.
+     *
+     * @return a list of tag post count projection
+     */
+    @Query("select new cc.ryanc.halo.model.projection.TagPostCountProjection(count(pt.postId), pt.tagId) from PostTag pt group by pt.tagId")
+    @NonNull
+    List<TagPostCountProjection> findPostCount();
 }

src/main/java/cc/ryanc/halo/service/impl/PostTagServiceImpl.java

@@ -4,6 +4,7 @@ import cc.ryanc.halo.model.dto.TagWithCountOutputDTO;
 import cc.ryanc.halo.model.entity.Post;
 import cc.ryanc.halo.model.entity.PostTag;
 import cc.ryanc.halo.model.entity.Tag;
+import cc.ryanc.halo.model.projection.TagPostCountProjection;
 import cc.ryanc.halo.repository.PostRepository;
 import cc.ryanc.halo.repository.PostTagRepository;
 import cc.ryanc.halo.repository.TagRepository;
@@ -59,9 +60,16 @@ public class PostTagServiceImpl extends AbstractCrudService<PostTag, Integer> im
         // Find all tags
         List<Tag> tags = tagRepository.findAll(sort);
 
+        // Find all post count
+        Map<Integer, Long> tagPostCountMap = ServiceUtils.convertToMap(postTagRepository.findPostCount(), TagPostCountProjection::getTagId, TagPostCountProjection::getCount);
+
         // Find post count
         return tags.stream().map(
-                tag -> new TagWithCountOutputDTO().<TagWithCountOutputDTO>convertFrom(tag)
+                tag -> {
+                    TagWithCountOutputDTO tagWithCountOutputDTO = new TagWithCountOutputDTO().convertFrom(tag);
+                    tagWithCountOutputDTO.setPostCount(tagPostCountMap.getOrDefault(tag.getId(), 0L));
+                    return tagWithCountOutputDTO;
+                }
         ).collect(Collectors.toList());
     }