// Indices for segments
  private static final int SEG_RAW   = 0;
  private static final int SEG_INDEX  = 1;
  private static final int SEG_TYPE   = 2;
  private static final int SEG_MODIFIER = 3; // modifier or subformat

/**
   * Sets the pattern used by this message format.
   * The method parses the pattern and creates a list of subformats
   * for the format elements contained in it.
   * Patterns and their interpretation are specified in the
   * <a href="#patterns" rel="external nofollow" >class description</a>.
   *
   * @param pattern the pattern for this message format
   * @exception IllegalArgumentException if the pattern is invalid
   */
  @SuppressWarnings("fallthrough") // fallthrough in switch is expected, suppress it
  public void applyPattern(String pattern) {
      StringBuilder[] segments = new StringBuilder[4];
      // Allocate only segments[SEG_RAW] here. The rest are
      // allocated on demand.
      segments[SEG_RAW] = new StringBuilder();

      int part = SEG_RAW;
      int formatNumber = 0;
      boolean inQuote = false;
      int braceStack = 0;
      maxOffset = -1;
      for (int i = 0; i < pattern.length(); ++i) {
        char ch = pattern.charAt(i);
        if (part == SEG_RAW) {
          if (ch == '\'') {
            if (i + 1 < pattern.length()
              && pattern.charAt(i+1) == '\'') {
              segments[part].append(ch); // handle doubles
              ++i;
            } else {
              inQuote = !inQuote;
            }
          } else if (ch == '{' && !inQuote) {
            part = SEG_INDEX;
            if (segments[SEG_INDEX] == null) {
              segments[SEG_INDEX] = new StringBuilder();
            }
          } else {
            segments[part].append(ch);
          }
        } else {
          if (inQuote) {       // just copy quotes in parts
            segments[part].append(ch);
            if (ch == '\'') {
              inQuote = false;
            }
          } else {
            switch (ch) {
            case ',':
              if (part < SEG_MODIFIER) {
                if (segments[++part] == null) {
                  segments[part] = new StringBuilder();
                }
              } else {
                segments[part].append(ch);
              }
              break;
            case '{':
              ++braceStack;
              segments[part].append(ch);
              break;
            case '}':
              if (braceStack == 0) {
                part = SEG_RAW;
                makeFormat(i, formatNumber, segments);
                formatNumber++;
                // throw away other segments
                segments[SEG_INDEX] = null;
                segments[SEG_TYPE] = null;
                segments[SEG_MODIFIER] = null;
              } else {
                --braceStack;
                segments[part].append(ch);
              }
              break;
            case ' ':
              // Skip any leading space chars for SEG_TYPE.
              if (part != SEG_TYPE || segments[SEG_TYPE].length() > 0) {
                segments[part].append(ch);
              }
              break;
            case '\'':
              inQuote = true;
              // fall through, so we keep quotes in other parts
            default:
              segments[part].append(ch);
              break;
            }
          }
        }
      }
      if (braceStack == 0 && part != 0) {
        maxOffset = -1;
        throw new IllegalArgumentException("Unmatched braces in the pattern.");
      }
      this.pattern = segments[0].toString();
  }