How standard types are named, and what is left out

A standard type's name says exactly what it is, and a type you might look for may be part of another or left for your app to define. Standard types lists every one, from A to Z and by group, and each has a page saying what it is and how to make one. Each part or kind a standard type names is a standard type too: IdentityDocument's IdentityDocumentKind, or RichText's RichTextBlock. GeoJSON's Feature and FeatureCollection are explained on the Geospatial page. Why Jadpo defines these types itself is in the design notes.

Three rules shape the list:

• Country-specific identifiers are global types, like the rest. UkSortCode, UsSsn and NhsNumber are named by their country, so they don't clash.
• Gender and sex at birth are left out. They are contested, and they are personal data, so your app models them deliberately, and Personal data treats them as sensitive.
• A quantity is stored in its SI base unit. You choose a unit when you make the value and when you show it: units.of(5, LengthUnit.mile) holds metres, and text.format(distance, locale:, unit: LengthUnit.mile) shows miles. So == and ordering just work, and storage is one numeric column.

How standard types are named

A standard type's name says exactly what it is, so it doesn't take a word your app needs for something else. The name is, in order of preference:

1. the defining standard's own term, qualified until it is unambiguous: PostalAddress, RecurrenceRule, ProblemDetails;
2. otherwise the noun, qualified by what it holds: DateRange, DataSize, ImageDimensions;
3. never a bare word an app plausibly uses for its own, different thing, except a generic container that takes a type, such as Range<T>, as List<T> is.

So it is CountrySubdivision, not Subdivision, which could be a housing subdivision, and UnitQuantity, not Quantity, which could be an order line's count. The same rule gives SecretText, NetworkPort, WritingScript and WebOrigin, and a time interval is the built-in InstantRange. A bare word passes when an app using it means the standard thing: Price, Area, Mass, Currency.

Point and Length are the two exceptions, so that geography and quantities read naturally (var shelf: Length = 2metre). Built-in names older than the rule (File, Page, Access) keep their names.

Types that aren't on the list

Some types you might look for are folded into another, so nothing is lost: units into their quantity type, roles into the general type, and duplicates into the one type they duplicate. Formats and application entities are left out:

What's left out on purpose

Some things you might reach for aren't in the standard library, each for a reason and with something to use instead: