[hibernate-dev] Merging hibernate spatial Dialects with the core ones

Tue Jun 28 11:19:15 EDT 2016

Thanks for the clarification.

However, all told I am not sure what you are suggesting.  Are you
suggesting that we somehow make Dialect itself expandable/mutable and
hibernate-spatial hook into that to expand mutate the ORM Dialect?

If it is just augmenting Types and SQLFunctions we already have
capabilities for this that I'd rather leverage:

   - For Types, hibernate-spatial would just provide a TypeContributor and
   based on the ORM Dialect it could contribute the needed Types.
   - We do not currently have a clean way to "contribute SQLFunctions" from
   an integration.  But if we are making changes anyway, I'd rather do this -
   adding a SqlFunctionContributor

If spatial dialects are really *only* used to contribute Types and
SQLFunctions,
the above options would remove the need for having spatial dialects at all
and still allow hibernate-spatial to contribute its things.

WDYT?

On Tue, Jun 28, 2016 at 9:18 AM Karel Maesen <karel at geovise.com> wrote:

> @Steve, besides Types a number of spatial Functions are registered for use
> in queries.
>
> The Dialect#contributetypes method is currently already used by
> Hibernate-spatial to inject to correct Types (with the correct
> SqlTypeDescriptors) for the SpatialDialect.
>
> On Tue, Jun 28, 2016 at 3:40 PM, Steve Ebersole <steve at hibernate.org>
> wrote:
>
>> I agree.  I think keeping these separate makes the most sense.
>>
>> @Karel, we already have that capability wrt Types (see
>> Dialect#contributeTypes).  What else would get injected?
>>
>> On Tue, Jun 28, 2016 at 8:33 AM Gunnar Morling <gunnar at hibernate.org>
>> wrote:
>>
>>> One thing to keep in mind is that the module system of Java 9 ("Jigsaw")
>>> doesn't support a notion of optional module dependences.
>>>
>>> So if this is meant to remain an "optional feature" (i.e. Geo-specific
>>> libraries are not required at runtime when not using the spatial stuff), it
>>> should remain a separate artifact - this is, should we plan to make
>>> Hibernate ORM JARs Jigsaw modules at some point.
>>>
>>> --Gunnar
>>>
>>>
>>> 2016-06-28 15:22 GMT+02:00 Karel Maesen <karel at geovise.com>:
>>>
>>>> It makes sense for some Dialects such as those for MySQL and MS SQL
>>>> Server.
>>>> Less so for Postgresql and Oracle Spatial because here the spatial
>>>> capabilities need to be installed and configured separately (and even
>>>> have
>>>> versioning separate from the main database engine).
>>>>
>>>> I would favour an approach, close to what Sanne is suggesting, where the
>>>> spatial capability (Incl. Types) is injected into the Dialect during
>>>> Dialect construction based on some explicit configuration. In that way
>>>> the
>>>> relation between Dialect and the spatial capability mirrors the relation
>>>> between database engine and spatial capability (if any).
>>>>
>>>> Regards,
>>>>
>>>> Karel
>>>>
>>>> PS: I'm leaving tomorrow on holiday for a couple of weeks so I won't be
>>>> able to resume the exchange before July 20.
>>>>
>>>> On Mon, Jun 27, 2016 at 3:53 PM, Steve Ebersole <steve at hibernate.org>
>>>> wrote:
>>>>
>>>> > They have not been "merged" in the same way we merged
>>>> > hibernate-entitymanager into hibernate-core.    So at the moment using
>>>> > hibernate-core e.g. does not require geolatte to be present.
>>>> geolatte is
>>>> > only required if using hibernate-spatial (isolated transitive dep).
>>>> >
>>>> > Karel, what are your thoughts on this?  I am not a fan of making
>>>> geolatte
>>>> > optional/provided, but if we all deem that folding hibernate-spatial
>>>> into
>>>> > hibernate-core (ala hibernate-entitymanager) as Vlad suggests is
>>>> desirable
>>>> > then I will accept that
>>>> >
>>>> > On Mon, Jun 27, 2016, 6:50 AM Sanne Grinovero <sanne at hibernate.org>
>>>> wrote:
>>>> >
>>>> > > Nice idea!
>>>> > >
>>>> > > since the modules were merged already, don't we already require
>>>> > > geolatte-geom ?
>>>> > > I guess some code might be intentionally designed to fail gracefully
>>>> > > about this library being there or not, but we'd need to make sure
>>>> that
>>>> > > can be tested for it to be maintainable.
>>>> > >
>>>> > > My preference would be to have:
>>>> > >  - All Dialects automatically provide the spatial extensions if the
>>>> > > needed dependencies are in place: we could automatically alias them
>>>> > > based on this?
>>>> > >  - a good error message naming the missing dependencies explicitly
>>>> > > when someone attempts to use such a Spatial extensions, but the
>>>> > > feature was not enabled by our automatic logic.
>>>> > >  - be able to test for these.
>>>> > >
>>>> > > In practice I believe this means we should still have it as an
>>>> > > independent source module, compile and test it as an independent
>>>> > > module, and only bundle within the ORM main jar as final
>>>> distribution
>>>> > > step.
>>>> > >
>>>> > > If that's too much work, I'd rather make the geolatte-geom a
>>>> mandatory
>>>> > > dependency than to have cryptic runtime failures.
>>>> > >
>>>> > > On 27 June 2016 at 12:41, Vlad Mihalcea <mihalcea.vlad at gmail.com>
>>>> wrote:
>>>> > > > Hi,
>>>> > > >
>>>> > > > Since hibenrate-spatial has been merged into Hibernate code base,
>>>> > > shouldn't
>>>> > > > we merge the Dialects as well.
>>>> > > > For instance, we have MySQL56InnoDBSpatialDialect which can
>>>> simply be
>>>> > > > merged into a MySQL56InnoDBDialect.
>>>> > > > This way, MySQL57InnoDBDialect can take advantage of spatial
>>>> queries as
>>>> > > > well.
>>>> > > >
>>>> > > > The only drawback is that we need to add the geolatte-geom lib to
>>>> > > > hibernate-orm.
>>>> > > >
>>>> > > > Let me know what you think.
>>>> > > >
>>>> > > > Vlad
>>>> > > > _______________________________________________
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