@Override
  public void prepare(EventSubscription entity, boolean update) {
    validateFilterRules(entity);
  }

  private void validateFilterRules(EventSubscription entity) {
    // Resolve JSON blobs into Rule object and perform schema based validation
    if (entity.getFilteringRules() != null) {
      List<EventFilterRule> rules = entity.getFilteringRules().getRules();
      // Validate all the expressions in the rule
      for (EventFilterRule rule : rules) {
        AlertUtil.validateExpression(rule.getCondition(), Boolean.class);
      }
      rules.sort(Comparator.comparing(EventFilterRule::getName));
    }
  }

public Response createOrUpdate(UriInfo uriInfo, SecurityContext securityContext, T entity) {
  repository.prepareInternal(entity, true);

  // If entity does not exist, this is a create operation, else update operation
  ResourceContext<T> resourceContext = getResourceContextByName(entity.getFullyQualifiedName());
  MetadataOperation operation = createOrUpdateOperation(resourceContext);
  OperationContext operationContext = new OperationContext(entityType, operation);
  if (operation == CREATE) {
    CreateResourceContext<T> createResourceContext = new CreateResourceContext<>(entityType, entity);
    authorizer.authorize(securityContext, operationContext, createResourceContext);
    entity = addHref(uriInfo, repository.create(uriInfo, entity));
    return new PutResponse<>(Response.Status.CREATED, entity, RestUtil.ENTITY_CREATED).toResponse();
  }
  authorizer.authorize(securityContext, operationContext, resourceContext);
  PutResponse<T> response = repository.createOrUpdate(uriInfo, entity);
  addHref(uriInfo, response.getEntity());
  return response.toResponse();
}

@PUT
@Operation(
    operationId = "createOrUpdateEventSubscription",
    summary = "Updated an existing or create a new Event Subscription",
    description = "Updated an existing or create a new Event Subscription",
    responses = {
      @ApiResponse(
          responseCode = "200",
          description = "create Event Subscription",
          content =
              @Content(
                  mediaType = "application/json",
                  schema = @Schema(implementation = CreateEventSubscription.class))),
      @ApiResponse(responseCode = "400", description = "Bad request")
    })
public Response createOrUpdateEventSubscription(
    @Context UriInfo uriInfo, @Context SecurityContext securityContext, @Valid CreateEventSubscription create) {
  // Only one Creation is allowed for Data Insight
  if (create.getAlertType() == CreateEventSubscription.AlertType.DATA_INSIGHT_REPORT) {
    try {
      repository.getByName(null, create.getName(), repository.getFields("id"));
    } catch (EntityNotFoundException ex) {
      if (ReportsHandler.getInstance() != null && ReportsHandler.getInstance().getReportMap().size() > 0) {
        throw new BadRequestException("Data Insight Report Alert already exists.");
      }
    }
  }
  EventSubscription eventSub = getEventSubscription(create, securityContext.getUserPrincipal().getName());
  Response response = createOrUpdate(uriInfo, securityContext, eventSub);
  repository.updateEventSubscription((EventSubscription) response.getEntity());
  return response;
}