* @return the change frequency
     */
    public String getChangefreq() {
        return changefreq;
    }

    /**
     * Sets the change frequency of this sitemap entry.
     * @param changefreq the change frequency to set
     */
    public void setChangefreq(final String changefreq) {
        this.changefreq = changefreq;
    }

    /**
     * Returns the priority of this sitemap entry.

      <lastmod>2005-01-01</lastmod>
      <changefreq>monthly</changefreq>
      <priority>0.8</priority>
   </url>
   <url>
      <loc>http://www.example.com/catalog?item=12&amp;desc=vacation_hawaii</loc>
      <changefreq>weekly</changefreq>
   </url>
   <url>
      <loc>http://www.example.com/catalog?item=73&amp;desc=vacation_new_zealand</loc>
      <lastmod>2004-12-23</lastmod>
      <changefreq>weekly</changefreq>
   </url>
   <url>

        // Invalid changefreq values should be preserved
        final String xml =
                "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" + "<urlset xmlns=\"http://www.sitemaps.org/schemas/sitemap/0.9\">\n"
                        + "  <url>\n" + "    <loc>http://www.example.com/page1.html</loc>\n" + "    <changefreq>sometimes</changefreq>\n"

        }
    }

    /**
     * Validates a changefreq value according to sitemap specification.
     * @param changefreq the changefreq to validate
     * @return true if valid, false otherwise
     */
    protected boolean isValidChangefreq(final String changefreq) {
        if (changefreq == null || changefreq.isEmpty()) {
            return true; // Changefreq is optional
        }