Refactor handling of content groups

Content groups are now a separate entity with their own repository and service and endpoint. A content group can no longer be set when creating a new content. Instead the new API endpoint has to be used to add the content to a group.

Refs #42 (closed), #45.

src/main/java/de/thm/arsnova/controller/v2/ContentController.java

@@ -27,6 +27,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 import javax.naming.OperationNotSupportedException;
@@ -45,12 +46,14 @@ import org.springframework.web.bind.annotation.RestController;
 import de.thm.arsnova.controller.PaginationController;
 import de.thm.arsnova.model.ChoiceAnswer;
 import de.thm.arsnova.model.ChoiceQuestionContent;
+import de.thm.arsnova.model.ContentGroup;
 import de.thm.arsnova.model.TextAnswer;
 import de.thm.arsnova.model.migration.FromV2Migrator;
 import de.thm.arsnova.model.migration.ToV2Migrator;
 import de.thm.arsnova.model.migration.v2.Answer;
 import de.thm.arsnova.model.migration.v2.Content;
 import de.thm.arsnova.service.AnswerService;
+import de.thm.arsnova.service.ContentGroupService;
 import de.thm.arsnova.service.ContentService;
 import de.thm.arsnova.service.RoomService;
 import de.thm.arsnova.service.TimerService;
@@ -73,6 +76,9 @@ public class ContentController extends PaginationController {
 	@Autowired
 	private ContentService contentService;
 
+	@Autowired
+	private ContentGroupService contentGroupService;
+
 	@Autowired
 	private AnswerService answerService;
 
@@ -97,7 +103,12 @@ public class ContentController extends PaginationController {
 	public Content getContent(@PathVariable final String contentId) {
 		final de.thm.arsnova.model.Content content = contentService.get(contentId);
 		if (content != null) {
-			return toV2Migrator.migrate(content);
+			Optional<ContentGroup> contentGroup = contentGroupService.getByRoomId(content.getRoomId()).stream()
+					.filter(cg -> cg.getContentIds().contains(contentId)).findFirst();
+			Content contentV2 = toV2Migrator.migrate(content);
+			contentGroup.ifPresent(cg -> contentV2.setQuestionVariant(cg.getName()));
+
+			return contentV2;
 		}
 
 		throw new NotFoundException();
@@ -115,6 +126,7 @@ public class ContentController extends PaginationController {
 		final String roomId = roomService.getIdByShortId(content.getSessionKeyword());
 		contentV3.setRoomId(roomId);
 		contentService.create(contentV3);
+		contentGroupService.addContentToGroup(roomId, content.getQuestionVariant(), contentV3.getId());
 
 		return toV2Migrator.migrate(contentV3);
 	}