String (@Nullable @NonNls String s, final ConvertContext context) { if (s == null) return null; if (myAllowEmpty && s.trim().length() == 0) return s; if (s.trim().length() == 1) return s; if (isUnicodeCharacterSequence(s)) { try { Integer.parseInt(s.substring(UNICODE_PREFIX.length()), 16); return s; } catch (NumberFormatException e) {} } return null; }