Support java.time.Instant and java.util.UUID types

[x80486]

Description

While testing Doma (and using java.time.Instant and/or java.util.UUID types) I'm always getting error messages like:

[DOMA4096] The class "java.util.UUID" is not supported as a persistent type. If you intend to map the class to the external domain class with @ExternalDomain, the configuration may be not enough. Check the class annotated with @DomainConverters and the annotation processing option "doma.domain.converters".
[DOMA4096] The class "java.time.Instant" is not supported as a persistent type. If you intend to map the class to the external domain class with @ExternalDomain, the configuration may be not enough. Check the class annotated with @DomainConverters and the annotation processing option "doma.domain.converters".

I think these two should be supported out-of-the-box by the framework since they are used widely for id and timestamp fields.

The same goes with java.time.ZonedDateTime.

Implementation Ideas

N/A

[nakamura-to]

Thanks for your feedback!

We don't support java.time.Instant and java.util.UUID currently because the JDBC specification does not support them. To support them, we need our own code for each JDBC driver.

We understand that there are situations where you want to use java.util.UUID.

However, we don't know when to use java.time.Instant, because you can use more specific types such as java.time.LocalTime, java.time.LocalDate and java.time.LocaDateTime. Let me know the situations where java.time.Instant is convenient.

[x80486]

Instant can be used in those types that store the time-zone, but it's not a standard JDBC type.

OffsetDateTime is a standard JDBC type, and what's used instead — although I find Instant way more intuitive.

UUID could be supported in those engines that supports it. Not sure if there is a way to cherry pick that functionality.