[threeten-dev] 2 digit year -> year date conversions for non-ISO calendars

[Stephen Colebourne]

While this fix solves the problem for YEAR, it wouldn't solve it for
WEEK_BASED_YEAR, or some other theoretical field.
Pattern uu would also have a problem I think.
Stephen

On 8 September 2013 20:13, roger riggs <roger.riggs at oracle.com> wrote:
> Hi,
>
> The parsing of the pattern "yy" is unambiguously spec'd to parse 2 digit
> years
> but  the DateTimeFormatterBuilder.appendValueReduced can be used for any
> field type not just YEAR.  So either the pattern mapping for 'yy' to
> reducedValue
> needs to map it to a different PrinterParser -or- the ReducedPrinterParser
> can be specialized to treat the YEAR field specially.  The special case
> defines the baseValue to be the ISO year and it is converted to the
> effective Chronology at the point that the value has been parsed and is
> being
> set in the Temporal.
>
> Please review and consider the solution in the webrev.
>   http://cr.openjdk.java.net/~rriggs/webrev-two-digit-8024076/
>
> Thanks, Roger
>
>
> [1] http://bugs.sun.com/view_bug.do?bug_id=8024076
> [2] http://cr.openjdk.java.net/~rriggs/webrev-two-digit-8024076/
>
>
>
>
> On 9/1/2013 8:35 PM, Roger RIggs wrote:
>>
>> Hi,
>>
>> The behavior of the parser for 2 digit years does not work as expected
>> for non-ISO calendars.  Due to the definition in DateTimeFormatterBuilder
>> of the "yy" pattern as being based on the year 2000 it only works for
>> The ISO and GregorianCalendars;  but for the ThaiBuddhistCalendar
>> with the year offset and for the HijrahCalendar it produces dates that
>> do not resolve correctly and causes an exception.
>>
>> For example,
>>
>>         Chronology chrono = ThaiBuddhistChronology.INSTANCE;
>>         Locale locale = Locale.getDefault(Locale.Category.FORMAT);
>>
>>         String pattern = "M/d/yy G";
>>         DateTimeFormatter df
>>                 = new DateTimeFormatterBuilder().appendPattern(pattern)
>>                 .toFormatter()
>>                 .withChronology(chrono);
>>
>>         ThaiBuddhistDate expected =
>> ThaiBuddhistChronology.INSTANCE.date(ThaiBuddhistEra.BE, 2576, 10, 29);
>>         String input = "10/29/76 B.E.";
>>
>>         parsed = df.parse(input);
>>         ThaiBuddhistDate actual = ThaiBuddhistDate.from(parsed);
>>         System.out.printf("pattern=%s, input=\"%s\", date=%s, TB date:
>> %s%n", pattern, input, parsed, actual);
>>
>> The output is:
>> pattern=M/d/yy G, input="10/29/76 B.E.", date={},ThaiBuddhist,null
>> resolved to ThaiBuddhist BE 2076-10-29,null, TB date: ThaiBuddhist BE
>> 2076-10-29
>> Expected: ThaiBuddhist BE 2576-10-29
>> Actual:   ThaiBuddhist BE 2076-10-29
>>
>> See JBS issue:
>>
>>  * JDK-8024076 <https://bugs.openjdk.java.net/browse/JDK-8024076>
>>    Incorrect 2 -> 4 year parsing and resolution in DateTimeFormatter
>>
>> Roger
>>
>>
>>
>>
>>
>