protected List parsePattern()

in log4j-core/src/main/java/org/apache/logging/log4j/core/util/datetime/FastDatePrinter.java [185:318]
126 lines of code
37 McCabe index (conditional complexity)

    protected List<Rule> parsePattern() {
        final DateFormatSymbols symbols = new DateFormatSymbols(mLocale);
        final List<Rule> rules = new ArrayList<>();

        final String[] ERAs = symbols.getEras();
        final String[] months = symbols.getMonths();
        final String[] shortMonths = symbols.getShortMonths();
        final String[] weekdays = symbols.getWeekdays();
        final String[] shortWeekdays = symbols.getShortWeekdays();
        final String[] AmPmStrings = symbols.getAmPmStrings();

        final int length = mPattern.length();
        final int[] indexRef = new int[1];

        for (int i = 0; i < length; i++) {
            indexRef[0] = i;
            final String token = parseToken(mPattern, indexRef);
            i = indexRef[0];

            final int tokenLen = token.length();
            if (tokenLen == 0) {
                break;
            }

            Rule rule;
            final char c = token.charAt(0);

            switch (c) {
                case 'G': // era designator (text)
                    rule = new TextField(Calendar.ERA, ERAs);
                    break;
                case 'y': // year (number)
                case 'Y': // week year
                    if (tokenLen == 2) {
                        rule = TwoDigitYearField.INSTANCE;
                    } else {
                        rule = selectNumberRule(Calendar.YEAR, tokenLen < 4 ? 4 : tokenLen);
                    }
                    if (c == 'Y') {
                        rule = new WeekYear((NumberRule) rule);
                    }
                    break;
                case 'M': // month in year (text and number)
                    if (tokenLen >= 4) {
                        rule = new TextField(Calendar.MONTH, months);
                    } else if (tokenLen == 3) {
                        rule = new TextField(Calendar.MONTH, shortMonths);
                    } else if (tokenLen == 2) {
                        rule = TwoDigitMonthField.INSTANCE;
                    } else {
                        rule = UnpaddedMonthField.INSTANCE;
                    }
                    break;
                case 'd': // day in month (number)
                    rule = selectNumberRule(Calendar.DAY_OF_MONTH, tokenLen);
                    break;
                case 'h': // hour in am/pm (number, 1..12)
                    rule = new TwelveHourField(selectNumberRule(Calendar.HOUR, tokenLen));
                    break;
                case 'H': // hour in day (number, 0..23)
                    rule = selectNumberRule(Calendar.HOUR_OF_DAY, tokenLen);
                    break;
                case 'm': // minute in hour (number)
                    rule = selectNumberRule(Calendar.MINUTE, tokenLen);
                    break;
                case 's': // second in minute (number)
                    rule = selectNumberRule(Calendar.SECOND, tokenLen);
                    break;
                case 'S': // millisecond (number)
                    rule = selectNumberRule(Calendar.MILLISECOND, tokenLen);
                    break;
                case 'E': // day in week (text)
                    rule = new TextField(Calendar.DAY_OF_WEEK, tokenLen < 4 ? shortWeekdays : weekdays);
                    break;
                case 'u': // day in week (number)
                    rule = new DayInWeekField(selectNumberRule(Calendar.DAY_OF_WEEK, tokenLen));
                    break;
                case 'D': // day in year (number)
                    rule = selectNumberRule(Calendar.DAY_OF_YEAR, tokenLen);
                    break;
                case 'F': // day of week in month (number)
                    rule = selectNumberRule(Calendar.DAY_OF_WEEK_IN_MONTH, tokenLen);
                    break;
                case 'w': // week in year (number)
                    rule = selectNumberRule(Calendar.WEEK_OF_YEAR, tokenLen);
                    break;
                case 'W': // week in month (number)
                    rule = selectNumberRule(Calendar.WEEK_OF_MONTH, tokenLen);
                    break;
                case 'a': // am/pm marker (text)
                    rule = new TextField(Calendar.AM_PM, AmPmStrings);
                    break;
                case 'k': // hour in day (1..24)
                    rule = new TwentyFourHourField(selectNumberRule(Calendar.HOUR_OF_DAY, tokenLen));
                    break;
                case 'K': // hour in am/pm (0..11)
                    rule = selectNumberRule(Calendar.HOUR, tokenLen);
                    break;
                case 'X': // ISO 8601
                    rule = Iso8601_Rule.getRule(tokenLen);
                    break;
                case 'z': // time zone (text)
                    if (tokenLen >= 4) {
                        rule = new TimeZoneNameRule(mTimeZone, mLocale, TimeZone.LONG);
                    } else {
                        rule = new TimeZoneNameRule(mTimeZone, mLocale, TimeZone.SHORT);
                    }
                    break;
                case 'Z': // time zone (value)
                    if (tokenLen == 1) {
                        rule = TimeZoneNumberRule.INSTANCE_NO_COLON;
                    } else if (tokenLen == 2) {
                        rule = Iso8601_Rule.ISO8601_HOURS_COLON_MINUTES;
                    } else {
                        rule = TimeZoneNumberRule.INSTANCE_COLON;
                    }
                    break;
                case '\'': // literal text
                    final String sub = token.substring(1);
                    if (sub.length() == 1) {
                        rule = new CharacterLiteral(sub.charAt(0));
                    } else {
                        rule = new StringLiteral(sub);
                    }
                    break;
                default:
                    throw new IllegalArgumentException("Illegal pattern component: " + token);
            }

            rules.add(rule);
        }

        return rules;
    }