protected function markPhysicallyUnavailable()
    {
        $this->is_physically_present = false;

        $this->mime = 'image/png';
        $this->width = 256;
        $this->height = 256;
        $this->file = $this->getSubstituteFilename();
        $this->etag = null;

        $this->path = $this->app['root.path'] . '/www/assets/common/images/icons/substitution/';
        $this->url = Url::factory('/assets/common/images/icons/substitution/' . $this->file);

        if (!file_exists($this->getRealPath())) {
            $this->path = $this->app['root.path'] . '/www/assets/common/images/icons/';
            $this->file = 'substitution.png';
            $this->url = Url::factory('/assets/common/images/icons/' . $this->file);
        }
    }