[threeten-dev] Review request for changes to support Hijrah variants

[Dan Chiba]

Hi Roger,

HijrahChronology.java
>   652     int getMaximumDayOfMonth() {
>   653         return 30;

At R.H. van Gent's website 
<http://www.staff.science.uu.nl/%7Egent0113/islam/ummalqura.htm>, it says:

"In some cases the advancement of the month can result in a month length 
of 31 days which is awkward as Islamic tradition only allows for month 
lengths of 29 or 30 days. In such cases one of the days in the month is 
reckoned twice. For instance, both Friday 28 December and Saturday 29 
December 2007 were reckoned as 19 Dhū ’l-Ḥijja 1428 AH."

This sounds astounding; I don't think 310 could support same date for 
two days, while a month longer (or shorter) than standard lengths might 
be supported.

Thanks,
-Dan

On 2/15/2013 1:16 PM, roger riggs wrote:
> Hi,
>
> Please review the changes to support multiple Islamic calendar variants:
>  - Only the Umm alQura variant is supported so far and is supported by 
> limited
>    placeholder data until the full data can be acquired and validated.
>  - Tests have been updated to work with the updated API and available 
> data
>  - The use of Locale 'ca' and 'cv' values has been added to 
> Chronology.ofLocale
>  - Properties are added to lib/calendars.properties to identify the 
> variants
>    by calendar type and to identify the resource containing the 
> calendar data.
>
> Webrev: http://cr.openjdk.java.net/~rriggs/webrev-hijrah-variants/
>
> Javadoc: http://cr.openjdk.java.net/~rriggs/javadoc-hijrah-variants/
>
> Note: there are several related issues to be addressed after this change:
>  - The API for Era.date(xxx) does not lend itself to support of calendars
>    with multiple variants; Eras do not have any knowledge of a 
> specific chronology
>  - Performance of initialization at startup
>  - Enumerations of Eras
>