Registering entities

AcrossHibernateJpaModule creates a Hibernate backed EntityManager for the classes assigned to it. Modules should tell the AcrossHibernateJpaModule where to scan for entities. The easiest way to do this is to register a module extension in the AcrossHibernateJpaModule with an @EntityScan for the correct packages.

Registering entities code implementing a HibernatePackageConfigurer
@ModuleConfiguration(AcrossHibernateJpaModule.NAME)
@EntityScan( basePackageClasses = MyEntities.class )
public class MyEntitiesConfiguration {
}

The location of MyEntitiesConfiguration in the above example would usually be in the extensions child package of that module’s root package.

Application module support

The application module is automatically scanned for entities if either of the following applies:

  • there is only the default AcrossHibernateJpaModule and property acrossHibernate.application.entity-scan is not false

  • property acrossHibernate.application.entity-scan is true

Advanced configuration

Apart from using @EntityScan there are different ways to register entities with AcrossHibernateJpaModule. To determined the entities it managed, any AcrossHibernateJpaModule creates a HibernatePackage with the same name as the module itself (AcrossHibernateJpaModule by default).

This package determines the entire mapping context that is available in the EntityManager. When bootstrapping, the AcrossHibernateJpaModule will delegate configuration to all HibernatePackageConfigurer beans found, followed by looking for @EntityScan annotated classes in its module context. As such, consuming modules can also inject a HibernatePackageConfigurer implementation into the JPA module using @ModuleConfiguration.

Example code using a HibernatePackageConfigurer
@ModuleConfiguration(AcrossHibernateJpaModule.NAME)
public class UserEntitiesConfiguration implements HibernatePackageConfigurer
{
	@Override
	public void configureHibernatePackage( HibernatePackageRegistry hibernatePackage ) {
		hibernatePackage.addPackageToScan( "com.foreach.across.modules.user.business" );
	}
}

The HibernatePackageConfigurer exposes the HibernatePackageRegistry which also allows you to register XML-based resources.

Unlike with @EntityScan the same configurer class can also be injected into multiple JPA modules. The HibernatePackageRegistry.getName() can then be used to discriminate between mapping contexts.
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