code: protected RegisteredService resolveRegisteredServiceInRequestContext(final RequestContext requestContext) {
          val resolvedService = resolveServiceFromAuthenticationRequest(requestContext);
          if (resolvedService != null) {
              val service = getWebflowEventResolutionConfigurationContext().getServicesManager().findServiceBy(resolvedService);
              RegisteredServiceAccessStrategyUtils.ensureServiceAccessIsAllowed(resolvedService, service);
              return service;
          }
          LOGGER.debug("Authentication request is not accompanied by a service given none is specified");
          return null;
      }
docs: Resolve registered service in request context.
  
  @param requestContext the request context
  @return the registered service