int startedCrawlerNum = 0;
        int activeCrawlerNum = 0;
        try {
            while (startedCrawlerNum < crawlerList.size()) {
                // Force to stop crawl
                if (systemHelper.isForceStop()) {
                    for (final Crawler crawler : crawlerList) {
                        crawler.stop();
                    }
                    break;
                }

        }

        int startedCrawlerNum = 0;
        int activeCrawlerNum = 0;
        while (startedCrawlerNum < dataCrawlingThreadList.size()) {
            // Force to stop crawl
            if (systemHelper.isForceStop()) {
                for (final DataCrawlingThread crawlerThread : dataCrawlingThreadList) {
                    crawlerThread.stopCrawling();
                }
                break;
            }

                    errorCount++;
                    logger.warn("Failed to access AccessResult data. Retrying... (attempt={}/{})", errorCount, maxErrorCount, e);
                } finally {
                    if (systemHelper.isForceStop()) {
                        finishCrawling = true;
                        if (logger.isDebugEnabled()) {
                            logger.debug("Stopped indexUpdater.");
                        }

    }

    /**
     * Checks if the system is in a force-stop state.
     *
     * @return true if the system is force-stopping, false otherwise.
     */
    public boolean isForceStop() {
        return forceStop.get();
    }

    /**
     * Sets the force-stop state of the system.
     *
     * @param b true to force-stop the system.
     */