#4107 Performance improvements for column sorting (sakaiproject#4108)

gradebookng/tool/src/java/org/sakaiproject/gradebookng/business/GradebookNgBusinessService.java

@@ -18,6 +18,7 @@
 import java.util.stream.Collectors;
 
 import javax.xml.bind.JAXBException;
+import lombok.RequiredArgsConstructor;
 
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.lang.builder.CompareToBuilder;
@@ -683,20 +684,19 @@ public List<GbStudentGradeInfo> buildGradeMatrix(final List<Assignment> assignme
 		// this gives us our base list and will be sorted as per our desired
 		// sort method
 		final List<User> students = getUsers(studentUuids);
-		if (settings.getStudentSortOrder() != null || settings.getNameSortOrder() != null) {
+		stopwatch.timeWithContext("buildGradeMatrix", "getUsers", stopwatch.getTime());
+		if (settings.getStudentSortOrder() != null) {
 
-			if (settings.getNameSortOrder() == GbStudentNameSortOrder.FIRST_NAME) {
-				Collections.sort(students, new FirstNameComparator());
-			} else {
-				Collections.sort(students, new LastNameComparator());
-			}
+			Comparator<User> comp = GbStudentNameSortOrder.FIRST_NAME == settings.getNameSortOrder() ?
+					new FirstNameComparator() : new LastNameComparator();
 
-			if (settings.getStudentSortOrder() != null &&
-					settings.getStudentSortOrder().equals(SortDirection.DESCENDING)) {
+			if (SortDirection.DESCENDING == settings.getStudentSortOrder()) {
 
-				Collections.reverse(students);
+				comp = Collections.reverseOrder(comp);
 			}
+			Collections.sort(students, comp);
 		}
+		stopwatch.timeWithContext("buildGradeMatrix", "sortUsers", stopwatch.getTime());
 
 		// get course grades
 		final Map<String, CourseGrade> courseGrades = getCourseGrades(studentUuids);
@@ -988,46 +988,42 @@ public List<GbStudentGradeInfo> buildGradeMatrix(final List<Assignment> assignme
 
 		// sort the matrix based on the supplied assignment sort order (if any)
 		if (settings.getAssignmentSortOrder() != null) {
-			final AssignmentGradeComparator comparator = new AssignmentGradeComparator();
-			comparator.setAssignmentId(settings.getAssignmentSortOrder().getAssignmentId());
+			Comparator<GbStudentGradeInfo> comparator = new AssignmentGradeComparator(settings.getAssignmentSortOrder().getAssignmentId());
 
 			final SortDirection direction = settings.getAssignmentSortOrder().getDirection();
-
-			// sort
-			Collections.sort(items, comparator);
-
 			// reverse if required
 			if (direction == SortDirection.DESCENDING) {
-				Collections.reverse(items);
+				comparator = Collections.reverseOrder(comparator);
 			}
+			// sort
+			Collections.sort(items, comparator);
 		}
 		stopwatch.timeWithContext("buildGradeMatrix", "matrix sorted by assignment", stopwatch.getTime());
 
 		// sort the matrix based on the supplied category sort order (if any)
 		if (settings.getCategorySortOrder() != null) {
-			final CategorySubtotalComparator comparator = new CategorySubtotalComparator();
-			comparator.setCategoryId(settings.getCategorySortOrder().getCategoryId());
+			Comparator comparator = new CategorySubtotalComparator(settings.getCategorySortOrder().getCategoryId());
 
 			final SortDirection direction = settings.getCategorySortOrder().getDirection();
-
-			// sort
-			Collections.sort(items, comparator);
-
 			// reverse if required
 			if (direction == SortDirection.DESCENDING) {
-				Collections.reverse(items);
+				comparator = Collections.reverseOrder(comparator);
 			}
+			// sort
+			Collections.sort(items, comparator);
+
 		}
 		stopwatch.timeWithContext("buildGradeMatrix", "matrix sorted by category", stopwatch.getTime());
 
 		if (settings.getCourseGradeSortOrder() != null) {
-			// sort
-			Collections.sort(items, new CourseGradeComparator(getGradebookSettings()));
 
+			Comparator<GbStudentGradeInfo> comp = new CourseGradeComparator(getGradebookSettings());
 			// reverse if required
 			if (settings.getCourseGradeSortOrder() == SortDirection.DESCENDING) {
-				Collections.reverse(items);
+				comp = Collections.reverseOrder(comp);
 			}
+			// sort
+			Collections.sort(items, comp);
 		}
 		stopwatch.timeWithContext("buildGradeMatrix", "matrix sorted by course grade", stopwatch.getTime());
 
@@ -2010,10 +2006,10 @@ public boolean isFinalGradeModeEnabled() {
 	 * has.
 	 *
 	 */
+	@RequiredArgsConstructor
 	class AssignmentGradeComparator implements Comparator<GbStudentGradeInfo> {
 
-		@Setter
-		private long assignmentId;
+		private final long assignmentId;
 
 		@Override
 		public int compare(final GbStudentGradeInfo g1, final GbStudentGradeInfo g2) {
@@ -2036,10 +2032,10 @@ public int compare(final GbStudentGradeInfo g1, final GbStudentGradeInfo g2) {
 	 * Note that this must have the categoryId set into it so we can extract the appropriate grade entry from the map that each student has.
 	 *
 	 */
+	@RequiredArgsConstructor
 	class CategorySubtotalComparator implements Comparator<GbStudentGradeInfo> {
 
-		@Setter
-		private long categoryId;
+		private final long categoryId;
 
 		@Override
 		public int compare(final GbStudentGradeInfo g1, final GbStudentGradeInfo g2) {