class ContentDisposition {

    public Optional<String> filename() {
        String filename = null;
        String value = parameters.get(FILENAME_PARAMETER);
        if (value != null) {
            filename = URLDecoder.decode(value, StandardCharsets.UTF_8);
        }
        return Optional.ofNullable(filename);
    }

    private  ContentDisposition(String type, Map<String, String> params);

}