private function _extract_filename()
    {

        if (empty($this->file)) return false;

        $tmp_array = explode('/', $this->file);
        $count     = (int)count($tmp_array);
        for ($i = 0; $i < $count; $i++) {
            if ($i + 1 == $count) {
                $this->filename = (string)$tmp_array[0];
            }
            array_shift($tmp_array);
        }
        unset($tmp_array);

        return true;
    }