Extend Language to ISO 639-3 codes

[mdoering]

Based on gbif/checklistbank#73 we need to deal with more languages than the current enum based on ISO 639-2 codes holds. The simplest option would be to extend the Language enum with all ~7700 codes and store both 2 and 3 letter codes as enum properties. But is a large enum like this still a good idea? Enum values are only initialised when they are first used, so should not be a JVM issue

[mdoering]

we have 186 entries now and use Locale to retrieve an english and native title.
That would also need to be explicitly listed in the extended enum

[mdoering]

The official list has only english titles: https://iso639-3.sil.org/sites/iso639-3/files/downloads/iso-639-3.tab

[mdoering]

I've quickly tried an extended enum and its not gonna work. Compilation error "Java code too large"

[marcos-lg]

This will be covered in #51

[MattBlissett]

Proposal:

Use java.util.Locale, with the property name languageTag, and serialize using BCP-47 (.toLanguageTag()). Alternatively, store just a String languageTag, specified to be BCP-47, and parse using Locale.

This seems to support pretty much everything, and moves the question of what values should be allowed to the classes. "Website language" might need 6+ constants defined, "User language" would need a list of living languages, and checklists can record any language -- it's up to the parser to decide what to do with fr, fr-LU and fr-FR.

new Locale.Builder()
  .setLanguage("zh").setScript("Hant").build().toLanguageTag() 
→ "zh-Hant"

new Locale.Builder()
  .setLanguage("es").setRegion("419").build().getDisplayName() 
→ "Spanish (Latin America and the Caribbean)"

// All the bits for Locale("en", "GB"):
en_GB
en
English
英文  // getDisplayLanguage(Locale.SIMPLIFIED_CHINESE)
GB
United Kingdom
English (United Kingdom)
eng
// (no script)
en-GB // toLanguageTag()

[MattBlissett]

I've run all the Crowdin language through Locale.Builder()... and it works. Crowdin include Klingon, en_JA (Jamaica is JM, and en_JM is present and works) and some other non-ISO codes. They can be stored in a Locale and retrieved, but the meanings might not be in Locale's dictionary.

All the GBIF Language enumeration values parse fine.

[mike-podolskiy90]

I'll try GbifUser with the Locale. Do we have add locale to the Organization class?