class AbstractRegistry implements Registry {

    protected static List<URL> filterEmpty(URL url, List<URL> urls) {
        if (CollectionUtils.isEmpty(urls)) {
            List<URL> result = new ArrayList<>(1);
            result.add(url.setProtocol(EMPTY_PROTOCOL));
            return result;
        }
        return urls;
    }

    public  AbstractRegistry(URL url);

}