[hibernate-dev] HHH-12125 - @GeneratedValue & 5.3

[Vlad Mihalcea]

That's a great idea. I stumbled on this issue many times, and it's very
good to simplify the mapping as you suggested.

+1

Vlad

On Sat, Nov 25, 2017 at 6:18 PM, Steve Ebersole <steve at hibernate.org> wrote:

> The background is all in the Jira, but the crux is this... it is better to
> allow a user to do this:
>
>     @GeneratedValue( strategy=SEQUENCE, generator="my_seq")
>
> rather than:
>
>     @GeneratedValue( strategy=SEQUENCE, generator="my_seq")
>     @SequenceGenerator( name="my_seq", sequenceName="my_seq" )
>
> You can see that `SequenceGenerator` is completely unnecessary in this case
> because it adds no new information beyond what is already available on the
> `@GeneratedValue`.
>
> This works great for `GeneratedValue#strategy=SEQUENCE` and
> `GeneratedValue#strategy=TABLE`, however consider this mapping:
>
>     @GeneratedValue( strategy=AUTO, generator="increment" )
>     @GenericGenerator( name = "increment", strategy = "increment" )
>
> Here we have the same underlying concern - the `@GenericGenerator` is just
> noise, it adds no additional information.  In keeping with the work done as
> part of HHH-12125 it would be great to allow users to instead just say:
>
>     @GeneratedValue( strategy=AUTO, generator="increment" )
>
> The problem here is that this last one is actually the responsibility of
> `org.hibernate.boot.model.IdGeneratorStrategyInterpreter
> #determineGeneratorName`
> to interpret, but it is not passed the `GeneratedValue#generator` value.
>
> So the easiest solution would be to add an additional parameter to
> `IdGeneratorStrategyInterpreter#determineGeneratorName` for passing in the
> generator name.  The concern here is that `IdGeneratorStrategyInterpreter`
> is defined in the API space and could very well have custom impls.
>
> A lesser solution wold be to add checks to the code that calls
> `IdGeneratorStrategyInterpreter#determineGeneratorName` to check for
> "magic" generator names before asking the
> `IdGeneratorStrategyInterpreter`.  This is just a very inflexible and
> non-extensible solution, but maybe this works for 5.3 and we can adjust
> `IdGeneratorStrategyInterpreter` as part of 6.0.
>
> Thoughts?
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