[hibernate-dev] org.hibernate.persister.spi.PersisterFactory and 5.0
Steve Ebersole
steve at hibernate.org
Mon Dec 1 15:22:44 EST 2014
Wanted to point out that I carried those signatures on to the persister
ctors as well.
In Amsterdam we had talked about OGM needing a bootstrap hook for the point
just after all persisters have been built. Exactly what information did
that hook need access to?
On Mon, Dec 1, 2014 at 11:28 AM, Steve Ebersole <steve at hibernate.org> wrote:
> As for the "parameter object", I came up with a decent (imo) solution. So
> I only wrap the things that are "contextual". Here is the contract right
> now:
>
>
> public interface PersisterFactory extends Service {
> /**
> * "Parameter object" providing access to additional information that may
> be needed
> * in the creation of the persisters.
> */
> public static interface PersisterCreationContext {
> SessionFactoryImplementor getSessionFactory();
> Metadata getMetadata();
> }
>
> /**
> * Create an entity persister instance.
> *
> * @param entityBinding The mapping information describing the entity
> * @param entityCacheAccessStrategy The cache access strategy for the
> entity region
> * @param naturalIdCacheAccessStrategy The cache access strategy for the
> entity's natural-id cross-ref region
> * @param creationContext Access to additional information needed to
> create an EntityPersister
> *
> * @return An appropriate entity persister instance.
> *
> * @throws HibernateException Indicates a problem building the persister.
> */
> public EntityPersister createEntityPersister(
> PersistentClass entityBinding,
> EntityRegionAccessStrategy entityCacheAccessStrategy,
> NaturalIdRegionAccessStrategy naturalIdCacheAccessStrategy,
> PersisterCreationContext creationContext) throws HibernateException;
>
> /**
> * Create a collection persister instance.
> *
> * @param collectionBinding The mapping information describing the
> collection
> * @param cacheAccessStrategy The cache access strategy for the collection
> region
> * @param creationContext Access to additional information needed to
> create an EntityPersister
> *
> * @return An appropriate collection persister instance.
> *
> * @throws HibernateException Indicates a problem building the persister.
> */
> public CollectionPersister createCollectionPersister(
> Collection collectionBinding,
> CollectionRegionAccessStrategy cacheAccessStrategy,
> PersisterCreationContext creationContext) throws HibernateException;
>
> }
>
> PersisterCreationContext is the contextual info. And it can be
> "statically" defined for each and every call into PersisterFactory. The
> other params to #createEntityPersister and #createCollectionPersister are
> specific to that call.
>
>
> On Thu, Nov 27, 2014 at 10:35 AM, Steve Ebersole <steve at hibernate.org>
> wrote:
>
>> Actually, I take that back about Metadata extending org.hibernate.cfg.Mappings.
>> I had contemplated doing that, but decided against it since Mappings
>> exposes all kinds of "extra" stuff that isn't actually mappings/metadata
>> (config info, contextual info, etc) and I did not want to fuglify these new
>> contracts that way.
>>
>> On Thu, Nov 27, 2014 at 10:25 AM, Steve Ebersole <steve at hibernate.org>
>> wrote:
>>
>>> 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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>>>>
>>>>
>>>
>>
>
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