protected function getMutexFile()
    {
        $file = false;

        if (true === $this->mutex) {
            $file = $this->getContainer()->getParameter('kernel.cache_dir')
                . '/'
                . Str::dash(lcfirst(Str::classname(get_class($this))))
                . '.lock';
        } elseif ($this->mutex) {
            $file = $this->mutex;
        }
        return $file;
    }