[hibernate-dev] org.hibernate.persister.spi.PersisterFactory and 5.0
Steve Ebersole
steve at hibernate.org
Thu Nov 27 11:25:50 EST 2014
Well naturally there is still access to all this information :)
IMO SessionFactoryObserver is a hack way of doing this. With 5.0, the way
to do this would be one of the various bootstrap hooks I mentioned
earlier. Specifically you want a hook that is called just after all
metadata is fully known.
BTW, for 5.0 the "metadata" is still using the mappings as defined in the
org.hibernate.mapping package. So all that code fragment will continue to
work aside from actually using the Configuration. Interestingly, had you
used org.hibernate.cfg.Mappings#iterateTables rather than
Configuration#getTableMappings(),
this code would have continued to work with no changes at all. This is the
point I made in the initial email about Metadata also being a
org.hibernate.cfg.Mappings.
On Thu, Nov 27, 2014 at 4:36 AM, Emmanuel Bernard <emmanuel at hibernate.org>
wrote:
> To add on Gunnar’s needs
>
> 3. Use Configuration to extract physical Table structure
>
> We also use configuration in the SchemaDefiner
> The SchemaDefiner received the Configuration from a custom implementation
> of SessionFactoryObserver and use it during sessionFactoryCreated.
>
> The reason we use Configuration is so that this SchemaDefiner contract can:
>
> - access to specific properties (say hibernate.0gm.neo4j.index create-drop
> )
> - get information about the table, it’s unique constraints as shown in
> this pseudo example
>
> Iterator<Table> tableMappings = configuration.getTableMappings();
> while ( tableMappings.hasNext() ) {
> Table table = tableMappings.next();
> if ( table.isPhysicalTable() ) {
> Label label = label( table.getName() );
> PrimaryKey primaryKey = table.getPrimaryKey();
> createConstraint( neo4jDb, table, label, primaryKey );
> @SuppressWarnings("unchecked")
> Iterator<Column> columnIterator = table.getColumnIterator();
> while ( columnIterator.hasNext() ) {
> Column column = columnIterator.next();
> if ( column.isUnique() ) {
> createUniqueConstraintIfMissing( neo4jDb, label,
> column.getName() );
> }
> }
> Iterator<UniqueKey> uniqueKeyIterator = table.getUniqueKeyIterator();
> while ( uniqueKeyIterator.hasNext() ) {
> createConstraint( neo4jDb, table, label, uniqueKeyIterator.next()
> );
> }
> }
> }
>
>
>
>
> On 27 Nov 2014, at 10:13, Gunnar Morling <gunnar at hibernate.org> wrote:
>
> 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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