*/
    public OptionalEntity<FessUser> login(final String username, final String password) {
        // Add defensive null/blank checks
        if (StringUtil.isBlank(username) || StringUtil.isBlank(password)) {
            if (logger.isDebugEnabled()) {
                logger.debug("Login failed: username or password is blank");
            }
            return OptionalEntity.empty();
        }

import org.codelibs.fess.sso.SsoResponseType;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.DocumentUtil;
import org.codelibs.opensearch.runner.net.OpenSearchCurl;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.web.login.credential.LoginCredential;
import org.lastaflute.web.response.ActionResponse;
import org.lastaflute.web.response.HtmlResponse;