/**
* Constructor
*
*/
public function __construct()
{
if ($this->_xml == NULL) {
$this->_xml = new XMLWriter();
}
$this->_xml->openMemory();
$this->_xml->startDocument('1.0', 'UTF-8');
$this->_xml->openURI('php://output');
$this->_xml->setIndent(true);
$this->_xml->startElement('response');
}