Method compile

classpath/java/util/regex/Compiler.java:372–532

(String regex)

  }

  public Pattern compile(String regex) {
    char[] array = regex.toCharArray();
    CharacterMatcher.Parser characterClassParser =
      new CharacterMatcher.Parser(array);
    for (int index = 0; index < array.length; ++ index) {
      char c = array[index];
      Group current = groups.peek();
      if (regularCharacter.matches(c)) {
        current.push(c);
        continue;
      }
      switch (c) {
      case '.':
        current.push(DOT);
        continue;
      case '\\':
        int unescaped = characterClassParser.parseEscapedCharacter(index + 1);
        if (unescaped >= 0) {
          index = characterClassParser.getEndOffset() - 1;
          current.push((char)unescaped);
          continue;
        }
        CharacterMatcher characterClass = characterClassParser.parseClass(index);
        if (characterClass != null) {
          index = characterClassParser.getEndOffset() - 1;
          current.push(new CharacterRange(characterClass));
          continue;
        }
        switch (array[index + 1]) {
        case 'b':
          index++;
          current.push(WORD_BOUNDARY);
          continue;
        case 'B':
          index++;
          current.push(NON_WORD_BOUNDARY);
          continue;
        }
        throw new RuntimeException("Parse error @" + index + ": " + regex);
      case '?':
      case '*':
      case '+': {
        boolean greedy = true;
        if (index + 1 < array.length && array[index + 1] == '?') {
          greedy = false;
          ++ index;
        }
        current.push(new Repeat(current.pop(),
          c == '+' ? 1 : 0, c == '?' ? 1 : -1, greedy));
        continue;
      }
      case '{': {
        ++ index;
        int length = characterClassParser.digits(index, 8, 10);
        int min = Integer.parseInt(regex.substring(index, index + length));
        int max = min;
        index += length - 1;
        c = index + 1 < array.length ? array[index + 1] : 0;