protected void startCrawling() {
        synchronized (crawlerContext.activeThreadCountLock) {
            crawlerContext.activeThreadCount++;
        }
    }

    protected void finishCrawling() {
        synchronized (crawlerContext.activeThreadCountLock) {
            crawlerContext.activeThreadCount--;
        }
    }

    protected boolean isContinue(final int tcCount) {
        if (!crawlerContainer.available()) {