DateTimeUtils.java 文件源码

private static PeriodFormatter cretePeriodFormatter(IntervalField startField, IntervalField endField)
{
    if (endField == null) {
        endField = startField;
    }

    List<PeriodParser> parsers = new ArrayList<>();

    PeriodFormatterBuilder builder = new PeriodFormatterBuilder();
    //CHECKSTYLE.OFF
    switch (startField) {
        case YEAR:
            builder.appendYears();
            parsers.add(builder.toParser());
            if (endField == IntervalField.YEAR) {
                break;
            }
            builder.appendLiteral("-");
        case MONTH:
            builder.appendMonths();
            parsers.add(builder.toParser());
            if (endField != IntervalField.MONTH) {
                throw new IllegalArgumentException("Invalid interval qualifier: " + startField + " to " + endField);
            }
            break;

        case DAY:
            builder.appendDays();
            parsers.add(builder.toParser());
            if (endField == IntervalField.DAY) {
                break;
            }
            builder.appendLiteral(" ");

        case HOUR:
            builder.appendHours();
            parsers.add(builder.toParser());
            if (endField == IntervalField.HOUR) {
                break;
            }
            builder.appendLiteral(":");

        case MINUTE:
            builder.appendMinutes();
            parsers.add(builder.toParser());
            if (endField == IntervalField.MINUTE) {
                break;
            }
            builder.appendLiteral(":");

        case SECOND:
            builder.appendSecondsWithOptionalMillis();
            parsers.add(builder.toParser());
    }
    //CHECKSTYLE.ON

    return new PeriodFormatter(builder.toPrinter(), new OrderedPeriodParser(parsers));
}