Store programme filter in session

src/main/java/nl/tudelft/queue/controller/EditionController.java

@@ -139,8 +139,8 @@ public class EditionController {
 	@GetMapping("/editions")
 	public String getEditionList(@AuthenticatedPerson Person person,
 			@PageableDefault(sort = "id", direction = Sort.Direction.DESC) Pageable pageable,
-			@RequestParam(required = false) List<Long> programs,
 			Model model) {
+		var programs = es.getFilter("/editions");
 		var editions = eApi
 				.getEditionsPageActiveOrTaughtBy(person.getId(), fromPageable(pageable), programs)
 				.block();
@@ -153,10 +153,25 @@ public class EditionController {
 		model.addAttribute("programs", cCache.getAll()
 				.stream().map(CourseDetailsDTO::getProgram).distinct()
 				.collect(Collectors.toList()));
+		model.addAttribute("filter", programs);
 
 		return "edition/index";
 	}
 
+	/**
+	 * Submits the programme filters for the editions page.
+	 *
+	 * @param  filter The programmes to filter on
+	 * @return        The page to load
+	 */
+	@PostMapping("/editions/filter")
+	public String submitFilters(@RequestParam(required = false) List<Long> filter,
+			RedirectAttributes redirectAttributes) {
+		es.storeFilter(filter, "/editions");
+		redirectAttributes.addAttribute("page", 0);
+		return "redirect:/editions";
+	}
+
 	/**
 	 * Gets the page for teachers to fill out when requesting a new course to be made.
 	 *