private static void createFileMaskRegExp(@NotNull String filter) throws PatternSyntaxException {
    String pattern;
    List<String> strings = StringUtil.split(filter, ",");
    if (strings.size() == 1) {
      pattern = PatternUtil.convertToRegex(filter.trim());
    }
    else {
      pattern = StringUtil.join(strings, s -> "(" + PatternUtil.convertToRegex(s.trim()) + ")", "|");
    }
    // just check validity
    //noinspection ResultOfMethodCallIgnored
    Pattern.compile(pattern, Pattern.CASE_INSENSITIVE);
  }
private static void createFileMaskRegExp(@NotNull String filter)