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 <gun...@hibernate.org> wrote:
>
> Hi,
>
> 2014-11-27 1:23 GMT+01:00 Steve Ebersole <st...@hibernate.org
> <mailto:st...@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
>
> <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
>
> <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
>
> <https://github.com/hibernate/hibernate-ogm/blob/master/core/src/main/java/org/hibernate/ogm/cfg/OgmConfiguration.java>
>
>
>
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