private boolean isValidFileName(String fileName) {
        if (fileName == null || fileName.length() > 255) {
            return false;
        }
          
        return fileName.matches("[^\\s\\\\/:\\*\\?\\\"<>\\|](\\x20|[^\\s\\\\/:\\*\\?\\\"<>\\|])*[^\\s\\\\/:\\*\\?\\\"<>\\|\\.]$");
}