@Override
            public String getIndexConfigIndex() {
                return "fess_config";
            }

            @Override
            public Integer getCoordinatorPollIntervalAsInteger() {
                return 60;
            }

            @Override
            public Integer getCoordinatorHeartbeatTtlAsInteger() {
                return 180000;
            }

        lastEventCheckTime = System.currentTimeMillis();

        sendHeartbeat();

        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final int interval = fessConfig.getCoordinatorPollIntervalAsInteger();
        pollTask = TimeoutManager.getInstance().addTimeoutTarget(this::poll, interval, true);

        if (logger.isInfoEnabled()) {

     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     * @throws NumberFormatException When the property is not integer.
     */
    Integer getCoordinatorPollIntervalAsInteger();

    /**
     * Get the value for the key 'coordinator.heartbeat.ttl'. <br>
     * The value is, e.g. 180000 <br>
     * comment: Time-to-live (ms) for instance heartbeat documents.