[hibernate-dev] org.hibernate.persister.spi.PersisterFactory and 5.0

[Gunnar Morling]

Hi,

2014-11-27 1:23 GMT+01:00 Steve Ebersole <steve at hibernate.org>:

> Part of the goals for ORM 5.0 is moving from Configuration to the
> ServiceRegistry+Metadata for building a SessionFactory.
>
> One of the points I ran into that will have to change
> is org.hibernate.persister.spi.PersisterFactory.  The problems is that
> PersisterFactory accepts a Configuration as part of building
> CollectionPersisters.  The need for Configuration in the standard
> CollectionPersister impls is amazingly trivial; we literally use it to
> locate the associated entity's PersistentClass to grab the classes dom4j
> node name, and this is right after we have just resolved the corresponding
> EntityPersister.  The point being that the standard CollectionPersisters
> really don't need access to the Configuration.
>
> I am pretty sure OGM provides a custom PersisterFactory, or is it just
> the PersisterClassResolver that OGM provides?  Also, I would assume OGM is
> providing custom CollectionPersister impls.  This change would affect both
> usages.
>

We don't have a custom PersisterFactory, but there are
OgmPersisterClassResolver [1] and OgmCollectionPersister [2]. In the latter
we accept a Configuration in the constructor but just pass it to the super
'ctor (AbstractCollectionPersister). We don't do anything ourselves with it.


> I wanted y'all to be aware of this upcoming change.  But I also wanted to
> start a discussion about what the signature(s) should become.  Currently we
> pass:
>
> * Configuration
> * Collection (the parsed mapping info)
> * CollectionRegionAccessStrategy
> * SessionFactoryImplementor
>
>
> I suggest we pass:
>
> * Collection
> * CollectionRegionAccessStrategy
> * SessionFactoryImplementor
> * Mapping
>

Should be fine for OGM. I suggest to wrap it into a parameter object
("PersisterInitializationContext" or so). That way stuff can be added down
the road without the need to instantly adapt existing persisters.

(I changed order to align with the order for building EntityPersisters)
>
> Mapping is org.hibernate.engine.spi.Mapping which is part of
> Configuration.  I decided to (at least temporarily) port this contract
> forward to ease migration.  Metadata implements it.
>
> There is a similar discussion to be had wrt Integrators.  I will follow up
> with an email specific to them later.
>

Regarding the removal of Configuration in general, there will be some more
work to be done in OGM. We have a custom sub-class, OgmConfiguration [3],
which is used for two purposes:

1) Set some properties automatically (to enable OGM's naming strategy and
query translator etc., use a specific mass indexer for Hibernate Search)
2) Provide an entry point into the API for setting store specific options,
e.g. like so:

    OgmConfiguration ogmCfg = ...;
    ogmCfg.configureOptionsFor( MongoDB.class )
        .entity( GolfPlayer.class )
            .writeConcern( WriteConcernType.REPLICA_ACKNOWLEDGED );

We'll need a way to still do 1).

2) is not really required. We provide an alternative anyways, for cases
where you don't bootstrap OGM yourself. You can specify a callback class
via configuration properties, which then will be invoked and provides the
entry point to the fluent API.

--Gunnar

[1]
https://github.com/hibernate/hibernate-ogm/blob/master/core/src/main/java/org/hibernate/ogm/jpa/impl/OgmPersisterClassResolver.java
[2]
https://github.com/hibernate/hibernate-ogm/blob/master/core/src/main/java/org/hibernate/ogm/persister/impl/OgmCollectionPersister.java
[3]
https://github.com/hibernate/hibernate-ogm/blob/master/core/src/main/java/org/hibernate/ogm/cfg/OgmConfiguration.java



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