public function login()
    {
        $result = $this->adapter->getResult();
        if ($result === self::PHAVOUR_AUTH_SERVICE_SUCCESS) {
            $auth = Auth::getInstance();
            $auth->login($this->adapter->getIdentity());
            $auth->setRoles($this->adapter->getRoles());

            return true;

        } elseif ($result === self::PHAVOUR_AUTH_SERVICE_INVALID) {
            throw new InvalidCredentialsException('Invalid credentials exception');
        }

        throw new UnrecognisedAuthenticationResultException('Expected 1 or 2');
    }