/** Fess log level configuration key. */
    public static final String FESS_LOG_LEVEL = "fess.log.level";

    /** Track total hits configuration key. */
    public static final String TRACK_TOTAL_HITS = "track_total_hits";

    /** System property prefix for Fess configuration. */
    public static final String SYSTEM_PROP_PREFIX = "fess.system.";

    /** Configuration prefix for Fess settings. */

                    .similarDocHash(params.getSimilarDocHash())
                    .responseFields(params.getResponseFields())
                    .searchRequestType(params.getType())
                    .trackTotalHits(params.getTrackTotalHits())
                    .minScore(params.getMinScore())
                    .build();
        };
    }

    /**