protected function generateExceptionMessage($reference)
    {
        $traces = debug_backtrace(false);

        $file = null;
        $line = null;

        foreach ($traces as $trace) {
            if (isset($trace['function']) && $trace['function'] == 'get' && isset($trace['class']) && $trace['class'] == __CLASS__) {
                $file = $trace['file'];
                $line = $trace['line'];
                break;
            }
        }

        $message = new ReferenceNotFoundMessage($reference, $file, $line);
        $message->setFrom($this->options['admin_email']);
        $message->setTo($this->options['admin_email']);

        return $message;
    }