add delete papers button

src/main/java/ru/ulstu/paper/controller/PapersView.java

@@ -8,6 +8,7 @@ import javax.annotation.PostConstruct;
 import javax.faces.view.ViewScoped;
 import javax.inject.Inject;
 import javax.inject.Named;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
@@ -19,6 +20,8 @@ public class PapersView {
 
     private List<Paper> papers;
 
+    private List<Paper> selectedPapers = new ArrayList<>();
+
     private String newPaperTitle;
 
     @PostConstruct
@@ -33,6 +36,10 @@ public class PapersView {
         papers = paperService.findAll();
     }
 
+    public void deleteSelected() {
+        paperService.delete(selectedPapers);
+    }
+
     public List<Paper.PaperStatus> getPaperStatuses() {
         return Arrays.asList(Paper.PaperStatus.values());
     }
@@ -48,4 +55,12 @@ public class PapersView {
     public void setNewPaperTitle(String newPaperTitle) {
         this.newPaperTitle = newPaperTitle;
     }
+
+    public List<Paper> getSelectedPapers() {
+        return selectedPapers;
+    }
+
+    public void setSelectedPapers(List<Paper> selectedPapers) {
+        this.selectedPapers = selectedPapers;
+    }
 }

src/main/java/ru/ulstu/paper/service/PaperService.java

@@ -437,4 +437,8 @@ public class PaperService {
         paper.getDeadlines().add(deadlineService.createWithOffset(new Date(), 1, ChronoUnit.WEEKS));
         create(paper);
     }
+
+    public void delete(List<Paper> papers) {
+        paperRepository.deleteInBatch(papers);
+    }
 }

src/main/resources/META-INF/resources/paper/papers.xhtml

@@ -40,6 +40,11 @@
                 </ui:include>
             </p:column>
         </p:dataTable>
+        <div class="ui-g-3">
+            <p:commandButton value="Удалить выделенные" disabled="#{papersView.selectedPapers.isEmpty()}"
+                             action="#{papersView.deleteSelected}" ajax="true" process="@form"
+                             update="messages @form mainForm:papersTable"/>
+        </div>
         <p:inputText placeholder="Создать новую статью" value="#{papersView.newPaperTitle}"/>
         <p:commandButton action="#{papersView.create}" value="Сохранить" ajax="true" process="@form"
                          update="messages @form mainForm:papersTable" style="visibility: hidden"/>