assertEquals("monthly", ((SitemapUrl) sitemaps[0]).getChangefreq());
        assertEquals("0.8", ((SitemapUrl) sitemaps[0]).getPriority());

        assertNull(sitemaps[1].getLastmod());
        assertEquals("http://www.example.com/catalog?item=12&desc=vacation_hawaii", sitemaps[1].getLoc());
        assertEquals("weekly", ((SitemapUrl) sitemaps[1]).getChangefreq());
        assertNull(((SitemapUrl) sitemaps[1]).getPriority());

     * @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;
    }

    /**

            return false;
        }
        // Validate optional fields
        if (!isValidPriority(sitemapUrl.getPriority())) {
            return false;
        }
        if (!isValidChangefreq(sitemapUrl.getChangefreq())) {
            return false;
        }
        if (!isValidDateFormat(sitemapUrl.getLastmod())) {
            return false;
        }
        return true;
    }