private function getFilesMaxAge($path, $names = array(), $default = 0)
    {
        $finder = new Finder();
        $finder->files()->in(realpath($path))->ignoreDotFiles(true);
        foreach ($names as $name) {
            $finder->name($name);
        }
        $ages = array();
        foreach ($finder as $file) {
            $ages[] = filemtime($file);
        }
        return max(array_merge($ages, array($default)));
    }