SkipSpaceClassesWithoutIdHibernateSpaceDataSource

SkipSpaceClassesWithoutIdHibernateSpaceDataSource.scala

class SkipSpaceClassesWithoutIdHibernateSpaceDataSource(@BeanProperty  val sessionFactory:SessionFactory) extends SpaceDataSource {

  protected final val logger: Logger = LoggerFactory.getLogger(getClass)

  import scala.collection.JavaConverters._


  lazy val managedEntries = sessionFactory.getAllClassMetadata.asScala.keySet

  lazy val initialLoadEntries = {
    val allClassMetaData = sessionFactory.getAllClassMetadata.asScala
    allClassMetaData flatMap {
      case (entityName,classMetaData) =>
      if(classMetaData.isInherited){
        val superClassEntityName: String = classMetaData.asInstanceOf[AbstractEntityPersister].getMappedSuperclass
        val superClassMetadata: ClassMetadata = allClassMetaData(superClassEntityName)
        val superClass: Class[_] = superClassMetadata.getMappedClass(EntityMode.POJO)
        if (superClass != null) {
            logger.debug("Entity {} is inherited and has a super class {} filtering it out for initial load managedEntries",entityName,superClass)
          None
        }
        else
          Some(entityName)

      }
      else
        Some(entityName)
    }
  }




  override def initialDataLoad: DataIterator[AnyRef] = {
    val session = sessionFactory.openSession()
    val iterators = initialLoadEntries map {
      entity => createIterator(session,entity)
    }
    val allIterators = iterators reduce { _ ++ _}
    new DataIterator[AnyRef]{

      def hasNext: Boolean = allIterators.hasNext

      def next(): AnyRef = HibernateIteratorUtils unproxy allIterators.next()

      def remove() {
        throw new UnsupportedOperationException("Can't remove from an hibernate iterator")}

      def close() {
        session.close()
      }
    }
  }

  def createIterator(session:Session,entityName:String):Iterator[AnyRef] = {
    val klass = Class forName entityName
    val spaceIdMethods = for {
      method <- klass.getMethods.toList if method.isAnnotationPresent(classOf[SpaceId])
    } yield method
    spaceIdMethods.length match{
      case 1 => {
        val criteria: Criteria = session createCriteria entityName
        criteria setCacheMode CacheMode.IGNORE
        criteria setCacheable false
        criteria setFlushMode FlushMode.MANUAL
        criteria.list.iterator().asInstanceOf[java.util.Iterator[AnyRef]].asScala
      }
      case 0 => Iterator.empty
      case _ =>       throw new IllegalStateException("A single SpaceId can be defined at maximum")
    }

  }



  override def supportsInheritance(): Boolean = false

  def shutdown() {
    logger.debug("Shutting down hibernate data source with embeddable support session factory")
  }

}

Elegant solution.