Add localized formatting to Seconds, Minutes, Hours, Days, Weeks, Months, Years.

[basil-bourque]

In the java.time classes, the DateTimeFormatter class offers ofLocalized… methods where localized text is generated to represent the date-time object's value, guided by the specified FormatStyle and Locale.

Example:

String output = myLocalDate.format( 
    DateTimeFormatter
    .ofLocalizedDate( FormatStyle.LONG )
    .withLocale( Locale.CANADA_FRENCH ) 
) ;

11 octobre 2018

It would be nice if the Seconds, Minutes, Hours, Days, Weeks, Months, and Years classes in ThreeTen-Extra could also generate localized text.

Someone asked for such localized text on Stack Overflow: Are there standard ways to accomplish localized date components on Android such as 1s, 1m, 1h, 1d, 1w, 1week, etc.

The example given in that posting, for a date component in English and a Spanish localization:

English (en):

• 3w
• 3 wks
• 3 weeks

Spanish (es):

• 3sem
• 3 sem
• 3 semanas

Possible solution: CLDR

According to JEP 252, the Unicode Consortium's Common Locale Data Repository (CLDR) has been bundled with Java 8 and later, at least in OpenJDK.

It seems like these values needed for this feature might be found in the CLDR if I am correctly reading the <relativeTime> item in section 3, Calendar Fields, of Unicode Technical Standard #35 UNICODE LOCALE DATA MARKUP LANGUAGE (LDML) PART 4: DATES:

relativeTime Display names for an instance of the field that is a counted number of units in the past or the future relative to the current instance; this needs plural forms. In English, data is provided for year, quarter, month, week, day, specific days of the week, ,hour, minute, and second.

[jodastephen]

This branch has work I started on this problem. The data is there (from Joda-Time) but I haven't got the time to fix the code. If anyone reading this wants to attempt a PR, please add a comment.

[monicagg]

I forked that branch and looked through source code. These few weeks I have time to contribute and soon will send a PR.

[jodastephen]

This has been merged.