Nette\Security\User::isLoggedIn PHP Method

    public function isLoggedIn()
    {
        return $this->storage->isAuthenticated();
    }

 /**
  * @inheritdoc
  */
 public function authorize($resource, $action, $parameters = NULL)
 {
     if (!$this->user->isLoggedIn()) {
         throw new AuthorizationException('User is not logged in.');
     }
     return TRUE;
 }