Fix and refactor lab statistic page

• Change the actRequestFreqChart !== null to a actRequestFreqChart != null in lab_status_charts.js to make sure that the graphs are created before they try to be accessed
• Change the return type of CourseStatusController methods to DTOs instead of HashMaps and edit the javascript accordingly

Closes #153 (closed)

src/main/java/nl/tudelft/ewi/queue/controller/CourseStatusController.java

@@ -17,12 +17,14 @@
  */
 package nl.tudelft.ewi.queue.controller;
 
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeSet;
 import java.util.stream.Collectors;
 
+import nl.tudelft.ewi.queue.dto.view.LabStatisticsViewDto;
+import nl.tudelft.ewi.queue.dto.view.RequestFrequencyViewDto;
+import nl.tudelft.ewi.queue.dto.view.RequestStatusViewDto;
 import nl.tudelft.ewi.queue.model.Assignment;
 import nl.tudelft.ewi.queue.model.Lab;
 import nl.tudelft.ewi.queue.model.Request;
@@ -44,21 +46,6 @@ public class CourseStatusController {
 	@Autowired
 	private LabStatusService lss;
 
-	/**
-	 * A data class to be sent over a network. This class distinguishes buckets and data. Buckets are the
-	 * start positions of each bucket in a histogram and the data is what is to be displayed in each bucket.
-	 */
-	public static class MultiFrequencies {
-		public List<Long> buckets;
-
-		public Map<String, List<Long>> data;
-
-		MultiFrequencies(List<Long> buckets, Map<String, List<Long>> data) {
-			this.buckets = buckets;
-			this.data = data;
-		}
-	}
-
 	/**
 	 * Creates and returns the data for a histogram regarding the status of requests over time. The data for
 	 * requests can be filtered on labs, assignments and rooms to only selectively count.
@@ -68,13 +55,13 @@ public class CourseStatusController {
 	 * @param  assignments The assignments to filter on.
 	 * @param  rooms       The rooms to filter on.
 	 * @param  nBuckets    The number of buckets to create. 4 by default (for 4 hours of lab).
-	 * @return             A MultiFrequencies object representing the buckets into which the lab was divided
-	 *                     and the number of requests created, open, and handled during each of the created
-	 *                     timeframes.
+	 * @return             A RequestFrequencyViewDto object representing the buckets into which the lab was
+	 *                     divided and the number of requests created, open, and handled during each of the
+	 *                     created time frames.
 	 */
 	@GetMapping("/course/{id}/status/freq/request")
 	@PreAuthorize("@permissionService.canViewStatus(principal, #id)")
-	public MultiFrequencies getRequestFrequencies(@PathVariable Long id,
+	public RequestFrequencyViewDto getRequestFrequencies(@PathVariable Long id,
 			@RequestParam(required = false, defaultValue = "") List<Lab> labs,
 			@RequestParam(required = false, defaultValue = "") List<Assignment> assignments,
 			@RequestParam(required = false, defaultValue = "") List<Room> rooms,
@@ -82,15 +69,11 @@ public class CourseStatusController {
 		List<Request> requests = lss.getFilteredRequests(labs, assignments, rooms);
 		TreeSet<Long> buckets = lss.createBucketsOverCourse(labs, nBuckets);
 
-		return new MultiFrequencies(
+		return new RequestFrequencyViewDto(
 				buckets.stream().sorted().collect(Collectors.toList()),
-				new HashMap<>() {
-					{
-						put("created", lss.countCreatedRequestsInBuckets(buckets, requests));
-						put("open", lss.countOpenRequestsInBuckets(buckets, requests));
-						put("handled", lss.countHandledRequestsInBuckets(buckets, requests));
-					}
-				});
+				lss.countCreatedRequestsInBuckets(buckets, requests),
+				lss.countOpenRequestsInBuckets(buckets, requests),
+				lss.countHandledRequestsInBuckets(buckets, requests));
 	}
 
 	/**
@@ -101,27 +84,23 @@ public class CourseStatusController {
 	 * @param  labs        The labs to filter on.
 	 * @param  assignments The assignments to filter on.
 	 * @param  rooms       The rooms to filter on.
-	 * @return             The data in the form of a mapping from names of statuses to the number of requests
-	 *                     counted with that status.
+	 * @return             The data in the form of a StatusViewDto.
 	 */
 	@GetMapping("/course/{id}/status/freq/status")
 	@PreAuthorize("@permissionService.canViewStatus(principal, #id)")
-	public Map<String, Long> getRequestStatusFrequencies(@PathVariable Long id,
+	public RequestStatusViewDto getRequestStatusFrequencies(@PathVariable Long id,
 			@RequestParam(required = false, defaultValue = "") List<Lab> labs,
 			@RequestParam(required = false, defaultValue = "") List<Assignment> assignments,
 			@RequestParam(required = false, defaultValue = "") List<Room> rooms) {
 		List<Request> requests = lss.getFilteredRequests(labs, assignments, rooms);
 
-		return new HashMap<>() {
-			{
-				put("pending", lss.countWhere(requests, Request::isPending));
-				put("processing", lss.countWhere(requests, Request::isProcessing));
-				put("approved", lss.countWhere(requests, Request::isApproved));
-				put("rejected", lss.countWhere(requests, Request::isRejected));
-				put("not_found", lss.countWhere(requests, Request::isNotFound));
-				put("revoked", lss.countWhere(requests, Request::isRevoked));
-			}
-		};
+		return new RequestStatusViewDto(
+				lss.countWhere(requests, Request::isPending),
+				lss.countWhere(requests, Request::isProcessing),
+				lss.countWhere(requests, Request::isApproved),
+				lss.countWhere(requests, Request::isRejected),
+				lss.countWhere(requests, Request::isNotFound),
+				lss.countWhere(requests, Request::isRevoked));
 	}
 
 	/**
@@ -134,29 +113,25 @@ public class CourseStatusController {
 	 * @param  labs        The labs to filter on.
 	 * @param  assignments The assignments to filter on.
 	 * @param  rooms       The rooms to filter on.
-	 * @return             The data in the form of a mapping from names to the measured data.
+	 * @return             The data in the form of a LabStatisticsViewDto.
 	 */
 	@GetMapping("/course/{id}/status/lab/info")
 	@PreAuthorize("@permissionService.canViewStatus(principal, #id)")
-	public Map<String, Object> getGenericLabInformation(@PathVariable Long id,
+	public LabStatisticsViewDto getGenericLabInformation(@PathVariable Long id,
 			@RequestParam(required = false, defaultValue = "") List<Lab> labs,
 			@RequestParam(required = false, defaultValue = "") List<Assignment> assignments,
 			@RequestParam(required = false, defaultValue = "") List<Room> rooms) {
 		List<Request> requests = lss.getFilteredRequests(labs, assignments, rooms);
 
-		return new HashMap<>() {
-			{
-				put("lab-static-noStudents", lss.countDistinctUsers(requests));
-				put("lab-static-noAssistants", lss.countDistinctAssistants(requests));
-				put("lab-static-nOpen", lss.countWhere(requests, Request::isPending));
-				put("lab-static-nHandled", lss.countWhere(requests, Request::isHandled));
-				put("lab-static-assignment",
-						lss.mostCountedName(lss.countRequestsPerAssignment(assignments, requests)));
-				put("lab-static-room", lss.mostCountedName(lss.countRequestsPerRoom(rooms, requests)));
-				put("lab-static-avgWaitingTime", lss.averageWaitingTime(requests));
-				put("lab-static-avgProcessingTime", lss.averageProcessingTime(requests));
-			}
-		};
+		return new LabStatisticsViewDto(
+				lss.countDistinctUsers(requests),
+				lss.countDistinctAssistants(requests),
+				lss.countWhere(requests, Request::isPending),
+				lss.countWhere(requests, Request::isHandled),
+				lss.mostCountedName(lss.countRequestsPerAssignment(assignments, requests)),
+				lss.mostCountedName(lss.countRequestsPerRoom(rooms, requests)),
+				lss.averageWaitingTime(requests),
+				lss.averageProcessingTime(requests));
 	}
 
 	/**