public function loadUserByUsername($username)
    {
        if (!$this->authTokenService->isValid($username)) {
            throw new UsernameNotFoundException("Invalid Token.");
        }

        try {

            return $this->authTokenService->getUser($username);
        } catch (ProgrammerException $ex) {
            throw new UsernameNotFoundException($ex->getMessage(), $ex->getCode());
        }
    }