Add moderators for rooms

Moderators can assist a room owner in managing the room. This commit
adds API and persistence support for moderators.

src/main/java/de/thm/arsnova/controller/RoomController.java

@@ -19,13 +19,22 @@ package de.thm.arsnova.controller;
 
 import de.thm.arsnova.model.Room;
 import de.thm.arsnova.service.RoomService;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import java.util.Set;
+
 @RestController
 @RequestMapping(RoomController.REQUEST_MAPPING)
 public class RoomController extends AbstractEntityController<Room> {
 	protected static final String REQUEST_MAPPING = "/room";
+	private static final String GET_MODERATORS_MAPPING = DEFAULT_ID_MAPPING + "/moderator";
+	private static final String MODERATOR_MAPPING = DEFAULT_ID_MAPPING + "/moderator/{userId}";
 
 	private RoomService roomService;
 
@@ -43,4 +52,29 @@ public class RoomController extends AbstractEntityController<Room> {
 	protected String resolveAlias(final String shortId) {
 		return roomService.getIdByShortId(shortId);
 	}
+
+	@GetMapping(GET_MODERATORS_MAPPING)
+	public Set<Room.Moderator> getModerators(@PathVariable final String id) {
+		return roomService.get(id).getModerators();
+	}
+
+	@PutMapping(MODERATOR_MAPPING)
+	public void putModerator(@PathVariable final String id, @PathVariable final String userId,
+			@RequestBody final Room.Moderator moderator) {
+		final Room room = roomService.get(id);
+		moderator.setUserId(userId);
+		if (moderator.getRoles().isEmpty()) {
+			moderator.getRoles().add(Room.Moderator.Role.EXECUTIVE_MODERATOR);
+		}
+		room.getModerators().removeIf(m -> m.getUserId().equals(userId));
+		room.getModerators().add(moderator);
+		roomService.update(room);
+	}
+
+	@DeleteMapping(MODERATOR_MAPPING)
+	public void deleteModerator(@PathVariable final String id, @PathVariable final String userId) {
+		final Room room = roomService.get(id);
+		room.getModerators().removeIf(m -> m.getUserId().equals(userId));
+		roomService.update(room);
+	}
 }

src/main/java/de/thm/arsnova/model/Room.java

@@ -98,6 +98,40 @@ public class Room extends Entity {
 		}
 	}
 
+	public static class Moderator {
+		public enum Role {
+			EDITING_MODERATOR,
+			EXECUTIVE_MODERATOR
+		}
+
+		private String userId;
+		private Set<Role> roles;
+
+		@JsonView({View.Persistence.class, View.Public.class})
+		public String getUserId() {
+			return userId;
+		}
+
+		@JsonView({View.Persistence.class, View.Public.class})
+		public void setUserId(final String userId) {
+			this.userId = userId;
+		}
+
+		@JsonView({View.Persistence.class, View.Public.class})
+		public Set<Role> getRoles() {
+			if (roles == null) {
+				roles = new HashSet<>();
+			}
+
+			return roles;
+		}
+
+		@JsonView({View.Persistence.class, View.Public.class})
+		public void setRoles(final Set<Role> roles) {
+			this.roles = roles;
+		}
+	}
+
 	public static class Settings {
 		private boolean questionsEnabled = true;
 		private boolean slidesEnabled = true;
@@ -420,6 +454,7 @@ public class Room extends Entity {
 	private String description;
 	private boolean closed;
 	private Set<ContentGroup> contentGroups;
+	private Set<Moderator> moderators;
 	private Settings settings;
 	private Author author;
 	private PoolProperties poolProperties;
@@ -509,6 +544,20 @@ public class Room extends Entity {
 		this.contentGroups = new HashSet<>(groups.values());
 	}
 
+	@JsonView(View.Persistence.class)
+	public Set<Moderator> getModerators() {
+		if (moderators == null) {
+			moderators = new HashSet<>();
+		}
+
+		return moderators;
+	}
+
+	@JsonView(View.Persistence.class)
+	public void setModerators(final Set<Moderator> moderators) {
+		this.moderators = moderators;
+	}
+
 	@JsonView({View.Persistence.class, View.Public.class})
 	public Settings getSettings() {
 		if (settings == null) {