Merge pull request 'pagination' (#6) from 5-pagination into master

Reviewed-on: #6

src/main/java/ru/ulstu/controller/NewsController.java

@@ -6,6 +6,7 @@
 
 package ru.ulstu.controller;
 
+import org.springframework.data.domain.Page;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.validation.BindingResult;
@@ -14,14 +15,21 @@ import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import ru.ulstu.model.News;
+import ru.ulstu.model.OffsetablePageRequest;
 import ru.ulstu.service.NewsService;
 
 import javax.validation.Valid;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
 
 @Controller
 @RequestMapping("news")
 public class NewsController {
+    private final static int DEFAULT_PAGE_SIZE = 10;
     private final NewsService newsService;
 
     public NewsController(NewsService newsService) {
@@ -29,8 +37,21 @@ public class NewsController {
     }
 
     @GetMapping("/news")
-    public String index(Model model) {
-        model.addAttribute("news", newsService.getAll());
+    public String listNews(Model model,
+                           @RequestParam Optional<Integer> page,
+                           @RequestParam Optional<Integer> size) {
+        int currentPage = page.orElse(1);
+        int pageSize = size.orElse(DEFAULT_PAGE_SIZE);
+
+        Page<News> newsPage = newsService.getNews(new OffsetablePageRequest(currentPage - 1, pageSize));
+        model.addAttribute("news", newsPage);
+        int totalPages = newsPage.getTotalPages();
+        if (totalPages > 0) {
+            List<Integer> pageNumbers = IntStream.rangeClosed(1, totalPages)
+                    .boxed()
+                    .collect(Collectors.toList());
+            model.addAttribute("pageNumbers", pageNumbers);
+        }
         return "news";
     }
 

src/main/java/ru/ulstu/model/OffsetablePageRequest.java

@@ -0,0 +1,93 @@
+package ru.ulstu.model;
+
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+
+import java.io.Serializable;
+
+public class OffsetablePageRequest implements Pageable, Serializable {
+    private final int offset;
+    private final int count;
+    private final Sort sort;
+
+    public OffsetablePageRequest(int page, long pageSize) {
+        this(pageSize * page, pageSize, Sort.by("id"));
+    }
+
+    public OffsetablePageRequest(long offset, long count, Sort sort) {
+        if (offset < 0) {
+            throw new IllegalArgumentException("Offset value must not be less than zero!");
+        }
+        if (count < 1) {
+            throw new IllegalArgumentException("Count value must not be less than one!");
+        }
+        this.offset = (int) offset;
+        this.count = (int) count;
+        this.sort = sort;
+    }
+
+    @Override
+    public Sort getSort() {
+        return sort;
+    }
+
+    @Override
+    public int getPageSize() {
+        return count;
+    }
+
+    @Override
+    public int getPageNumber() {
+        return offset / count;
+    }
+
+    @Override
+    public long getOffset() {
+        return offset;
+    }
+
+    @Override
+    public boolean hasPrevious() {
+        return offset > 0;
+    }
+
+    @Override
+    public Pageable next() {
+        return new OffsetablePageRequest(getOffset() + getPageSize(), getPageSize(), getSort());
+    }
+
+    @Override
+    public Pageable previousOrFirst() {
+        return hasPrevious() ? previous() : first();
+    }
+
+    public Pageable previous() {
+        return getOffset() == 0 ? this : new OffsetablePageRequest(getOffset() - getPageSize(), getPageSize(), getSort());
+    }
+
+    @Override
+    public Pageable first() {
+        return new OffsetablePageRequest(0, getPageSize(), getSort());
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final OffsetablePageRequest other = (OffsetablePageRequest) obj;
+        return this.offset == other.offset && this.count == other.count;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + offset;
+        result = prime * result + count;
+        return result;
+    }
+}

src/main/java/ru/ulstu/repository/NewsRepository.java

@@ -1,5 +1,7 @@
 package ru.ulstu.repository;
 
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 import ru.ulstu.model.News;
 
@@ -7,4 +9,6 @@ import java.util.List;
 
 public interface NewsRepository extends JpaRepository<News, Integer> {
     List<News> findFirst3ByOrderByDateDesc();
+
+    Page<News> findByOrderByDateDesc(Pageable pageable);
 }

src/main/java/ru/ulstu/service/NewsService.java

@@ -1,5 +1,7 @@
 package ru.ulstu.service;
 
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 import ru.ulstu.model.News;
 import ru.ulstu.repository.NewsRepository;
@@ -50,4 +52,8 @@ public class NewsService {
     public List<News> getLast() {
         return newsRepository.findFirst3ByOrderByDateDesc();
     }
+
+    public Page<News> getNews(Pageable pageable) {
+        return newsRepository.findByOrderByDateDesc(pageable);
+    }
 }

src/main/resources/public/css/main.css

@@ -31,4 +31,25 @@
 
 .link-dark, .link-dark:visited, .link-dark:focus, .link-dark:any-link {
     color: black;
-}
+}
+
+.pagination {
+    display: inline-block;
+}
+
+.pagination a {
+    color: black;
+    float: left;
+    padding: 5px 5px;
+    text-decoration: none;
+}
+
+.pagination a.active {
+    background-color: gray;
+    color: white;
+    border-radius: 2px;
+}
+
+footer {
+    height: 50px;
+}

src/main/resources/templates/admin.html

@@ -7,7 +7,7 @@
 <!DOCTYPE html SYSTEM "http://www.thymeleaf.org/dtd/xhtml1-strict-thymeleaf-spring4-4.dtd">
 <html xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout" layout:decorate="~{default}">
 <div class="container" layout:fragment="content">
-    <a href="/editNews/0" class="btn btn-outline-dark">
+    <a href="/news/editNews/0" class="btn btn-outline-dark">
         <i class="fa fa-plus-square" aria-hidden="true">Добавить новость</i>
     </a>
 </div>

src/main/resources/templates/default.html

@@ -64,6 +64,7 @@
         <div layout:fragment="content">
         </div>
     </div>
+    <footer></footer>
 </div>
 </body>
 </html>

src/main/resources/templates/news.html

@@ -36,5 +36,15 @@
              class="news-date"></div>
         <hr/>
     </div>
+    <div th:if="${news.totalPages > 0}" class="pagination">
+        <span style="float: left; padding: 5px 5px;">Страницы:</span>
+    </div>
+    <div th:if="${news.totalPages > 0}" class="pagination"
+         th:each="pageNumber : ${pageNumbers}">
+        <a th:href="@{/news/news(size=${news.size}, page=${pageNumber})}"
+           th:text=${pageNumber}
+           th:class="${pageNumber == news.number+1} ? active"></a>
+    </div>
+
 </div>
 </html>