public function readFile()
    {
        try {
            $id = $this->readString();
            return $this->getFileManager()->retrieve($id);
        } catch (\Exception $e) {
            $msg = "An error occured while writing a QTI File.";
            throw new QtiBinaryStreamAccessException($msg, $this, QtiBinaryStreamAccessException::FILE, $e);
        }
    }