if (StringUtils.isEmpty(nonce) || !nonce.equals(stateData.getNonce())) {
                throw new SsoLoginException("could not validate nonce");
            }
        } catch (final SsoLoginException e) {
            throw e;
        } catch (final Exception e) {
            throw new SsoLoginException("could not validate nonce", e);
        }
    }

    /**
     * Obtains an access token using a refresh token.

import org.codelibs.fess.app.web.base.login.SamlCredential;
import org.codelibs.fess.app.web.base.login.SamlCredential.SamlUser;
import org.codelibs.fess.crawler.Constants;
import org.codelibs.fess.exception.SsoLoginException;
import org.codelibs.fess.exception.SsoMessageException;
import org.codelibs.fess.exception.SsoProcessException;
import org.codelibs.fess.mylasta.action.FessUserBean;
import org.codelibs.fess.sso.SsoAuthenticator;