public function setRequest($request)
    {
        if (is_string($request) && class_exists($request)) {
            $request = new $request();
            if (!$request instanceof Zend_Amf_Request) {
                require_once 'Zend/Amf/Server/Exception.php';
                throw new Zend_Amf_Server_Exception('Invalid request class');
            }
        } elseif (!$request instanceof Zend_Amf_Request) {
            require_once 'Zend/Amf/Server/Exception.php';
            throw new Zend_Amf_Server_Exception('Invalid request object');
        }
        $this->_request = $request;
        return $this;
    }