throw new UnsupportedOperationException("checkUserLoginable is not supported.");
    }

    @Override
    protected void checkCredential(final TypicalLoginAssist<String, FessUserBean, FessUser>.CredentialChecker checker) {
        throw new UnsupportedOperationException("checkCredential is not supported.");
    }

    @Override
    protected OptionalEntity<FessUser> doFindLoginUser(final String username) {