Table of Contents
The EntityManagerFactory
creates
EntityManager
instances for application use.
OpenJPA extends the standard EntityManagerFactory
interface with the
OpenJPAEntityManagerFactory
to provide additional
functionality.
Within a container, you will typically use injection to
access an EntityManagerFactory
. There are, however,
alternative mechanisms for EntityManagerFactory
construction.
Some vendors may supply public constructors for their
EntityManagerFactory
implementations, but we recommend using the
Java Connector Architecture (JCA) in a managed environment, or the
Persistence
class' createEntityManagerFactory
methods in an unmanaged environment, as described in
Chapter 6,
Persistence
. These strategies allow
vendors to pool factories, cutting down on resource utilization.
JPA allows you to create and configure an
EntityManagerFactory
, then store it in a Java Naming and Directory
Interface (JNDI) tree for later retrieval and use.