add @Convert(to = ....class)

[gavinking]

see #619

[yrodiere]

I wonder if something like as() wouldn't be less confusing here... because this is fundamentally not a one-way conversion.

But then as is a keyword in Groovy, so there's that.

[gavinking]

I think if it were @Persist or @Treat then as would be better. But "convert as string" isn't grammatically correct.

[gavinking]

If we're going to touch this stuff, we should take the opportunity to bless the use of @Convert as a meta-annotation, as discussed in #43.

[gavinking]

@sebersole Are you in favor of doing this one in JPA4?

Or should we put it on ice for reconsideration as part of 4.1, where we're already considering other longstanding enhancements to converters (composite converters #105, and @Convert as a meta-annotation #73)?

[sebersole]

Like we discussed in chat, I'd be inclined to (also?) expose this on @Column. E.g.

@Column(type=String.class)
UUID uuid;

Which, granted, implies some level of implicit conversion. But you already called that out, and I don't think needs to be a huge set for the spec itself - providers could ofc provide extended set of conversions if they wish

[gavinking]

Yeah so I'm trying to think this through.

• There's something appealing about putting it on @Column because it really is just the column type you're specifying, and to the extend that there's a converter, it's entirely implicit and theoretical.
• On the other hand, it feels at least a bit strange to me to be specifying a column type as a Java type., and I feel like this sorta pushes me back in the direction of the place I actually started out at which was @Column(jdbcType=Types.BIGINT).