private static final String DUPLICATE_HOST_HELPER = "duplicateHostHelper";

    private static final String PATH_MAPPING_HELPER = "pathMappingHelper";

    private static final String POPULAR_WORD_HELPER = "popularWordHelper";

    private static final String CRAWLING_INFO_HELPER = "crawlingInfoHelper";

    private static final String CRAWLING_CONFIG_HELPER = "crawlingConfigHelper";

    /** The key of the configuration. e.g. 10 */
    String SUGGEST_POPULAR_WORD_SIZE = "suggest.popular.word.size";

    /** The key of the configuration. e.g. 30 */
    String SUGGEST_POPULAR_WORD_WINDOW_SIZE = "suggest.popular.word.window.size";

    /** The key of the configuration. e.g. 10 */
    String SUGGEST_POPULAR_WORD_QUERY_FREQ = "suggest.popular.word.query.freq";

                } catch (final SuggesterException e) {
                    logger.warn("Failed to generate popular words.", e);
                }

                return wordList;
            });
        } catch (final ExecutionException e) {
            logger.warn("Failed to load popular words.", e);
        }
        return Collections.emptyList();
    }

    public void clearCache() {

    public static final String WEB_API_SUGGEST_PROPERTY = "web.api.suggest";

    public static final String WEB_API_GSA_PROPERTY = "web.api.gsa";

    public static final String WEB_API_POPULAR_WORD_PROPERTY = "web.api.popularword";

    public static final String APP_VALUE_PROPERTY = "system.properties";

    public static final String DEFAULT_LABEL_VALUE_PROPERTY = "label.value";

    /** The key of the message: Fess */
    public static final String LABELS_search_title = "{labels.search_title}";

    /** The key of the message: Popular Words: */
    public static final String LABELS_search_popular_word_word = "{labels.search_popular_word_word}";

    /** The key of the message: Related Words: */
    public static final String LABELS_search_related_queries = "{labels.search_related_queries}";

                return FormatType.SCROLL;
            }
            return FormatType.SEARCH;
        }
        if ("labels".equals(type)) {
            return FormatType.LABEL;
        }
        if ("popular-words".equals(type)) {
            return FormatType.POPULARWORD;
        }
        if ("favorites".equals(type)) {
            return FormatType.FAVORITES;
        }
        if ("health".equals(type)) {

    }

    default void setWebApiPopularWord(final boolean value) {
        setSystemPropertyAsBoolean(Constants.WEB_API_POPULAR_WORD_PROPERTY, value);
    }

    default boolean isWebApiPopularWord() {
        return getSystemPropertyAsBoolean(Constants.WEB_API_POPULAR_WORD_PROPERTY, true);
    }

    default void setCsvFileEncoding(final String value) {