Method render

/**
 * Render the document
 *
 * @param   boolean  $cache   If true, cache the output
 * @param   array    $params  Associative array of attributes
 *
 * @return  string The rendered data
 *
 * @since   1.7.0
 * @throws  \Exception
 * @todo    Make this cacheable
 */
public function render($cache = false, $params = array())
{
    // Get the feed type
    $type = CmsFactory::getApplication()->input->get('type', 'rss');
    // Instantiate feed renderer and set the mime encoding
    $renderer = $this->loadRenderer($type ?: 'rss');
    if (!$renderer instanceof DocumentRenderer) {
        throw new \Exception(Text::_('JGLOBAL_RESOURCE_NOT_FOUND'), 404);
    }
    $this->setMimeEncoding($renderer->getContentType());
    // Output
    // Generate prolog
    $data = "<?xml version=\"1.0\" encoding=\"" . $this->_charset . "\"?>\n";
    $data .= "<!-- generator=\"" . $this->getGenerator() . "\" -->\n";
    // Generate stylesheet links
    foreach ($this->_styleSheets as $src => $attr) {
        $data .= "<?xml-stylesheet href=\"{$src}\" type=\"" . $attr['type'] . "\"?>\n";
    }
    // Render the feed
    $data .= $renderer->render();
    parent::render($cache, $params);
    return $data;
}