public function setUsages(FileManager $file_manager)
    {
        $usages = array();
        $usage_class = $file_manager->getUsagesClass();
        if ($usage_class != false) {
            /** @var mixed $usage_object */
            $usage_object = new $usage_class;
            $usages_result = $usage_object->returnUsages($this->getFilepath(true));
            if (!empty($usages_result)) {
                $usages = $usages_result;
            }
        }
        $this->usages = count($usages);
    }