protected function getAdapterFactory()
    {
        if (!isset($this->factoryCache[$this->id])) {
            $config = config('jwt');
            if (isset($this->config['adapter'])) {
                $config = array_merge($config, $this->config['adapter']);
            }
            $factoryClass = $this->getAdapterFactoryClass();
            $this->factoryCache[$this->id] = new $factoryClass($config);
        }
        return $this->factoryCache[$this->id];
    }