private AsciiSet charClass()

in spectator-api/src/main/java/com/netflix/spectator/impl/matcher/Parser.java [223:303]
81 lines of code
20 McCabe index (conditional complexity)

  private AsciiSet charClass() {
    AsciiSet tmp;
    AsciiSet set = AsciiSet.none();
    boolean rangeStart = false;
    boolean invert = peek() == '^';
    if (invert) {
      advance();
      set = AsciiSet.all();
    }
    if (peek() == ']' || peek() == '-') {
      char c = advance();
      set = update(set, AsciiSet.fromPattern(Character.toString(c)), invert);
    }
    while (!isAtEnd() && peek() != ']') {
      char c = advance();
      switch (c) {
        case '[':
          set = set.union(charClass());
          rangeStart = false;
          break;
        case '&':
          if (peek() == '&') {
            advance();
            if (peek() == '[') {
              advance();
              set = set.intersection(charClass());
            } else if (peek() != ']') {
              set = set.intersection(charClass());
              --current;
            }
          } else {
            set = update(set, AsciiSet.fromPattern(Character.toString(c)), invert);
          }
          rangeStart = false;
          break;
        case '\\':
          tmp = namedCharClass();
          if (tmp == null) {
            c = advance();
            rangeStart = true;
            set = update(set, AsciiSet.fromPattern(Character.toString(c)), invert);
          } else {
            rangeStart = false;
            set = update(set, tmp, invert);
          }
          break;
        case '-':
          if (rangeStart && peek() != ']') {
            if (peek() == '\\') {
              advance();
              tmp = namedCharClass();
              if (tmp == null) {
                String range = tokens.subSequence(current - 3, current - 1).toString() + peek();
                if (range.endsWith("\\")) {
                  advance();
                }
                set = update(set, AsciiSet.fromPattern(range), invert);
              } else {
                set = update(set, AsciiSet.fromPattern("-"), invert);
                set = update(set, tmp, invert);
              }
            } else {
              String range = tokens.subSequence(current - 2, current + 1).toString();
              set = update(set, AsciiSet.fromPattern(range), invert);
            }
          } else {
            set = update(set, AsciiSet.fromPattern("-"), invert);
          }
          rangeStart = false;
          break;
        default:
          rangeStart = true;
          set = update(set, AsciiSet.fromPattern(Character.toString(c)), invert);
          break;
      }
    }
    if (advance() != ']') {
      throw error("unclosed character class");
    }
    return set;
  }