return getAsInteger(FessConfig.search_engine_HTTP_SSL_certificate_authorities);
        }

        public String getSearchEngineUsername() {
            return get(FessConfig.search_engine_USERNAME);
        }

        public Integer getSearchEngineUsernameAsInteger() {
            return getAsInteger(FessConfig.search_engine_USERNAME);
        }

    }

    Integer getAsInteger(String propertyKey);

    Integer getSearchEngineHeartbeatIntervalAsInteger();

    default long getFesenHeartbeatInterval() {
        Integer value = getSearchEngineHeartbeatIntervalAsInteger();
        if (value != null) {
            return value.longValue();
        }
        value = getAsInteger("elasticsearch.heartbeat_interval");