private int executorTerminationTimeout = 300;

    public FileListIndexUpdateCallbackImpl(final IndexUpdateCallback indexUpdateCallback, final CrawlerClientFactory crawlerClientFactory,
            final int nThreads) {
        this.indexUpdateCallback = indexUpdateCallback;
        this.crawlerClientFactory = crawlerClientFactory;
        executor = newFixedThreadPool(nThreads < 1 ? 1 : nThreads);