In-memory sorting of roles returned by RoleService#search

src/main/java/eu/europa/ec/simpl/usersroles/services/impl/RoleServiceImpl.java

@@ -21,7 +21,6 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.UUID;
-import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import lombok.SneakyThrows;
@@ -227,23 +226,23 @@ public class RoleServiceImpl implements RoleService {
 
     private Comparator<? super RoleDTO> toComparator(Sort sort) {
         return sort.stream()
-                .flatMap(order -> {
-                    try {
-                        return Optional.ofNullable(getPropertyDescriptor(order)).flatMap(toComparator(order)).stream();
-                    } catch (BeansException e) {
-                        return Stream.empty();
-                    }
-                })
+                .flatMap(this::toComparator)
                 .reduce(Comparator::thenComparing)
                 .orElse(unsortedComparator());
     }
 
-    private static PropertyDescriptor getPropertyDescriptor(Sort.Order order) {
-        return BeanUtils.getPropertyDescriptor(RoleDTO.class, order.getProperty());
+    private Stream<Comparator<RoleDTO>> toComparator(Sort.Order order) {
+        try {
+            return Optional.ofNullable(getPropertyDescriptor(order))
+                    .flatMap(property -> toComparator(property, order.getDirection()))
+                    .stream();
+        } catch (BeansException e) {
+            return Stream.empty();
+        }
     }
 
-    private static Function<PropertyDescriptor, Optional<Comparator<RoleDTO>>> toComparator(Sort.Order order) {
-        return property -> toComparator(property, order.getDirection());
+    private static PropertyDescriptor getPropertyDescriptor(Sort.Order order) {
+        return BeanUtils.getPropertyDescriptor(RoleDTO.class, order.getProperty());
     }
 
     private static Optional<Comparator<RoleDTO>> toComparator(PropertyDescriptor property, Sort.Direction direction) {