OZG-6897 cleanup

user-manager-server/src/main/java/de/ozgcloud/user/UserResourceMapper.java

@@ -36,6 +36,7 @@ import java.util.stream.Stream;
 
 import jakarta.inject.Inject;
 
+import org.apache.commons.lang3.StringUtils;
 import org.keycloak.admin.client.resource.RealmResource;
 import org.keycloak.admin.client.resource.UserResource;
 import org.keycloak.representations.idm.ClientMappingsRepresentation;
@@ -83,8 +84,7 @@ public abstract class UserResourceMapper {
 						getOrganisationsEinheitIdsFromGroups(groups),
 						getOrganisationsEinheitIdsFromUser(userRes)
 				)
-				.filter(Objects::nonNull)
-				.filter(oeId -> !oeId.isBlank())
+				.filter(StringUtils::isNotBlank)
 				.collect(Collectors.toSet());
 	}
 
@@ -93,12 +93,12 @@ public abstract class UserResourceMapper {
 				.map(this::mapGroup)
 				.filter(Objects::nonNull)
 				.map(attributeMap -> attributeMap.get(properties.organisationsEinheitIdKey()))
-				.filter(Objects::nonNull)
 				.flatMap(Collection::stream);
 	}
 
 	private Stream<String> getOrganisationsEinheitIdsFromUser(UserResource userRes) {
-		return Optional.ofNullable(getUserAttributes(userRes).get(properties.organisationsEinheitIdKey()))
+		return getUserAttributes(userRes)
+				.map(attributes -> attributes.get(properties.organisationsEinheitIdKey()))
 				.orElse(Collections.emptyList())
 				.stream();
 	}
@@ -124,7 +124,7 @@ public abstract class UserResourceMapper {
 
 		return Optional.ofNullable(userRepresentation.getAttributes())
 				.map(attributes -> attributes.get(properties.ldapIdKey()))
-				.map(id -> id.get(0))
+				.map(List::getFirst)
 				.orElseGet(userRepresentation::getId);
 
 	}
@@ -159,7 +159,7 @@ public abstract class UserResourceMapper {
 				.filter(Objects::nonNull).toArray(String[]::new));
 	}
 
-	private Map<String, List<String>> getUserAttributes(UserResource userResource) {
-		return Optional.ofNullable(userResource.toRepresentation().getAttributes()).orElse(Map.of());
+	private Optional<Map<String, List<String>>> getUserAttributes(UserResource userResource) {
+		return Optional.ofNullable(userResource.toRepresentation().getAttributes());
 	}
 }