Summary

Persistence manager factories, and in some cases connection factories, produce persistence managers. The persistence manager factory informs the application about the general capabilities of the implementation. In particular, the factory identifies the optional JDO features that the implementation supports.

The factories directly provide objects that implement the PersistenceManager interface and indirectly provide objects that implement the Transaction interface. The values of two of the persistence manager's properties and five of the transaction's properties are inherited from the factory that produces them. The persistence manager uses the values of the factory's connection properties when connecting to the datastore. In addition, when there is a container-managed transaction, the factories enlist the persistence manager in the managed transaction.

The next chapter completes this book's description of JDO's persistence service by examining the utility class JDOHelper, the callback interface InstanceCallbacks, and exception hierarchy descending from JDOException. Each of these serve a special purpose, and every application will use some of them.