* crawler may only retrieve Sitemaps that were modified since a certain
     * date. This incremental Sitemap fetching mechanism allows for the rapid
     * discovery of new URLs on very large sites.
     */
    private String lastmod;

    /**
     * Creates a new SitemapFile instance.
     */
    public SitemapFile() {
        // Default constructor
    }

    /*
     * (non-Javadoc)