@Override
  public Pair<Boolean, ActionOnFailedAuthentication> authenticate(
      String username, String password, Long domainId, Map<String, Object[]> requestParameters) {
    if (s_logger.isDebugEnabled()) {
      s_logger.debug("Trying SAML2 auth for user: "******"Username or Password cannot be empty");
      return new Pair<Boolean, ActionOnFailedAuthentication>(false, null);
    }

    final UserAccount userAccount = _userAccountDao.getUserAccount(username, domainId);
    if (userAccount == null || userAccount.getSource() != User.Source.SAML2) {
      s_logger.debug(
          "Unable to find user with "
              + username
              + " in domain "
              + domainId
              + ", or user source is not SAML2");
      return new Pair<Boolean, ActionOnFailedAuthentication>(false, null);
    } else {
      User user = _userDao.getUser(userAccount.getId());
      if (user != null
          && user.getSource() == User.Source.SAML2
          && user.getExternalEntity() != null) {
        return new Pair<Boolean, ActionOnFailedAuthentication>(true, null);
      }
    }
    // Deny all by default
    return new Pair<Boolean, ActionOnFailedAuthentication>(
        false, ActionOnFailedAuthentication.INCREMENT_INCORRECT_LOGIN_ATTEMPT_COUNT);
  }