ConstraintViolation<?> validateBlobStoreNotInGroup(final String blobStoreName) { return blobStoreManager.getParent(blobStoreName).map(groupName -> constraintViolationFactory .createViolation(format("%s.%s.blobStoreName", P_ATTRIBUTES, STORAGE), format("Blob Store '%s' is a member of Blob Store Group '%s' and cannot be set as storage", blobStoreName, groupName))).orElse(null); }