list recent article

src/main/java/io/spring/api/ArticlesApi.java

@@ -2,6 +2,7 @@ package io.spring.api;
 
 import com.fasterxml.jackson.annotation.JsonRootName;
 import io.spring.api.exception.InvalidRequestException;
+import io.spring.application.Page;
 import io.spring.application.article.ArticleQueryService;
 import io.spring.core.article.Article;
 import io.spring.core.article.ArticleRepository;
@@ -13,9 +14,11 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
 import javax.validation.Valid;
@@ -52,6 +55,15 @@ public class ArticlesApi {
             put("article", articleQueryService.findById(article.getId(), user).get());
         }});
     }
+
+    @GetMapping
+    public ResponseEntity getArticles(@RequestParam(value = "offset", defaultValue = "0") int offset,
+                                      @RequestParam(value = "limit", defaultValue = "20") int limit,
+                                      @RequestParam(value = "tag", required = false) String tag,
+                                      @RequestParam(value = "favorited", required = false) String favoritedBy,
+                                      @RequestParam(value = "author", required = false) String author) {
+        return ResponseEntity.ok(articleQueryService.findRecentArticles(tag, author, favoritedBy, new Page(offset, limit)));
+    }
 }
 
 @Getter

src/main/java/io/spring/application/Page.java

@@ -0,0 +1,33 @@
+package io.spring.application;
+
+import lombok.Data;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Data
+@Getter
+@NoArgsConstructor
+public class Page {
+    private static final int MAX_LIMIT = 100;
+    private int offset = 0;
+    private int limit = 20;
+
+    public Page(int offset, int limit) {
+        setOffset(offset);
+        setLimit(limit);
+    }
+
+    private void setOffset(int offset) {
+        if (offset > 0) {
+            this.offset = offset;
+        }
+    }
+
+    private void setLimit(int limit) {
+        if (limit > MAX_LIMIT) {
+            this.limit = MAX_LIMIT;
+        } else if (limit > 0) {
+            this.limit = limit;
+        }
+    }
+}

src/main/java/io/spring/application/article/ArticleDataList.java

@@ -0,0 +1,20 @@
+package io.spring.application.article;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import lombok.Getter;
+
+import java.util.List;
+
+@Getter
+public class ArticleDataList {
+    @JsonProperty("articles")
+    private final List<ArticleData> articleDatas;
+    @JsonProperty("articlesCount")
+    private final int count;
+
+    public ArticleDataList(List<ArticleData> articleDatas, int count) {
+
+        this.articleDatas = articleDatas;
+        this.count = count;
+    }
+}

src/main/java/io/spring/application/article/ArticleQueryService.java

@@ -1,10 +1,13 @@
 package io.spring.application.article;
 
+import io.spring.application.Page;
 import io.spring.application.profile.UserRelationshipQueryService;
 import io.spring.core.user.User;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Optional;
 
 @Service
@@ -54,4 +57,12 @@ public class ArticleQueryService {
                 user.getId(),
                 articleData.getProfileData().getId()));
     }
+
+    public ArticleDataList findRecentArticles(String tag, String author, String favoritedBy, Page page) {
+        List<String> articleIds = articleReadService.queryArticles(tag, author, favoritedBy, page);
+        int articleCount = articleReadService.countArticle(tag, author, favoritedBy);
+        return new ArticleDataList(
+            articleIds.size() == 0 ? new ArrayList<>() : articleReadService.findArticles(articleIds),
+            articleCount);
+    }
 }

src/main/java/io/spring/application/article/ArticleReadService.java

@@ -1,13 +1,22 @@
 package io.spring.application.article;
 
+import io.spring.application.Page;
 import org.apache.ibatis.annotations.Mapper;
 import org.apache.ibatis.annotations.Param;
 import org.springframework.stereotype.Component;
 
+import java.util.List;
+
 @Component
 @Mapper
 public interface ArticleReadService {
     ArticleData findById(@Param("id") String id);
 
     ArticleData findBySlug(@Param("slug") String slug);
+
+    List<String> queryArticles(@Param("tag") String tag, @Param("author") String author, @Param("favoritedBy") String favoritedBy, @Param("page") Page page);
+
+    int countArticle(@Param("tag") String tag, @Param("author") String author, @Param("favoritedBy") String favoritedBy);
+
+    List<ArticleData> findArticles(@Param("articleIds") List<String> articleIds);
 }

src/main/java/io/spring/core/article/Article.java

@@ -27,6 +27,10 @@ public class Article {
     private DateTime updatedAt;
 
     public Article(String title, String description, String body, String[] tagList, String userId) {
+        this(title, description, body, tagList, userId, new DateTime());
+    }
+
+    public Article(String title, String description, String body, String[] tagList, String userId, DateTime createdAt) {
         this.id = UUID.randomUUID().toString();
         this.slug = toSlug(title);
         this.title = title;
@@ -34,8 +38,8 @@ public class Article {
         this.body = body;
         this.tags = Arrays.stream(tagList).collect(toSet()).stream().map(Tag::new).collect(toList());
         this.userId = userId;
-        this.createdAt = new DateTime();
-        this.updatedAt = new DateTime();
+        this.createdAt = createdAt;
+        this.updatedAt = createdAt;
     }
 
     public void update(String title, String description, String body) {

src/main/resources/mapper/ArticleReadService.xml

@@ -33,6 +33,59 @@
         <include refid="selectArticleData"/>
         where A.slug = #{slug}
     </select>
+    <select id="queryArticles" resultMap="articleId">
+        select
+        DISTINCT(A.id) articleId, A.created_at
+        from
+        articles A
+        left join article_tags AT on A.id = AT.article_id
+        left join tags T on T.id = AT.tag_id
+        left join article_favorites AF on AF.article_id = A.id
+        <where>
+            <if test="tag != null">
+                T.name = #{tag}
+            </if>
+            <if test="author != null">
+                AND A.user_id = #{author}
+            </if>
+            <if test="favoritedBy != null">
+                AND AF.user_id = #{favoritedBy}
+            </if>
+        </where>
+        order by A.created_at desc
+        limit #{page.offset}, #{page.limit}
+    </select>
+    <select id="countArticle" resultType="java.lang.Integer">
+        select
+        count(DISTINCT A.id)
+        from
+        articles A
+        left join article_tags AT on A.id = AT.article_id
+        left join tags T on T.id = AT.tag_id
+        left join article_favorites AF on AF.article_id = A.id
+        <where>
+            <if test="tag != null">
+                T.name = #{tag}
+            </if>
+            <if test="author != null">
+                AND A.user_id = #{author}
+            </if>
+            <if test="favoritedBy != null">
+                AND AF.user_id = #{favoritedBy}
+            </if>
+        </where>
+    </select>
+    <select id="findArticles" resultMap="articleData">
+        <include refid="selectArticleData"/>
+        where A.id in
+        <foreach index="index" collection="articleIds" item="id" open="(" separator="," close=")">
+            #{id}
+        </foreach>
+    </select>
+
+    <resultMap id="articleId" type="string">
+        <id javaType="string" column="articleId"/>
+    </resultMap>
 
     <resultMap id="articleData" type="io.spring.application.article.ArticleData">
         <id column="articleId" property="id"/>