/** The key of the configuration. e.g. 60 */
    String SUGGEST_POPULAR_WORD_CACHE_EXPIRE = "suggest.popular.word.cache.expire";

    /** The key of the configuration. e.g. {user}guest,{role}guest */
    String SUGGEST_SEARCH_LOG_PERMISSIONS = "suggest.search.log.permissions";

    /** The key of the configuration. e.g. 60 */
    String SUGGEST_SYSTEM_MONITOR_INTERVAL = "suggest.system.monitor.interval";