public void addSitemap(final Sitemap sitemap) {
        sitemapList.add(sitemap);
    }

    /**
     * Removes a sitemap from this set.
     * @param sitemap the sitemap to remove
     */
    public void removeSitemap(final Sitemap sitemap) {
        sitemapList.remove(sitemap);
    }

    /**
     * Gets all sitemaps in this set as an array.
     * @return an array of sitemaps
     */
    public Sitemap[] getSitemaps() {

        // Should be null after removal
        assertNull(crawlerContext.removeSitemaps());

        // Test with null
        crawlerContext.addSitemaps(null);
        assertNull(crawlerContext.removeSitemaps());

        // Test with empty array
        crawlerContext.addSitemaps(new String[0]);
        String[] emptyArray = crawlerContext.removeSitemaps();
        assertNotNull(emptyArray);

    }

    /**
     * Removes sitemaps from the thread-local storage and returns them.
     * @return An array of sitemap URLs, or null if none were present.
     */
    public String[] removeSitemaps() {
        final String[] sitemaps = sitemapsLocal.get();
        if (sitemaps != null) {
            sitemapsLocal.remove();
        }
        return sitemaps;
    }

     * @param urlQueue The URL queue to add sitemaps to.
     */
    protected void addSitemapsFromRobotsTxt(final UrlQueue<?> urlQueue) {
        final String[] sitemaps = crawlerContext.removeSitemaps();
        if (sitemaps != null) {
            for (final String childUrl : sitemaps) {
                try {
                    storeChildUrl(childUrl, urlQueue.getUrl(), urlQueue.getWeight(),