Store multiple persistence units in one entity manager factory?

[Bobby Anderson]

I am a little confused so please bear with me.

I have two persistence units myPU1 and myPU2. Each is defined in a separate jar file. I want to get both of these persistence units into JNDI.

I also want both persistence units in the same entity manager factory (if that is possible)

I know that I have to use one of the following properties in my persistence.xml but I am not sure which or if I need both:

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
	version="1.0">

	<persistence-unit name="myPU1" transaction-type="JTA">
		<jta-data-source>java:myDS</jta-data-source>  
		<properties>
			<!-- Store entity manager and factory in global JNDI -->
        	<property name="jboss.entity.manager.jndi.name" value="myPU1"/>
         	<property name="jboss.entity.manager.factory.jndi.name" value="myPU1"/>
		</properties>
		
	</persistence-unit>
</persistence>

I have another file that is identical except for the persistence unit name (myPU2). Can I bind both of those to the same factory?

[Jaikiran Pai]

Billy Newman wrote:

I have another file that is identical except for the persistence unit name (myPU2). Can I bind both of those to the same factory?

A entity manager factory is == persistence unit. So if you have two persistence units, then it would effectively mean you have two entity manager factories.

[Bobby Anderson]

so if an entity manager factory = persistence unit, what is a entity manager = ?

[Jaikiran Pai]

Billy Newman wrote:so if an entity manager factory = persistence unit, what is a entity manager = ?

entity manager = persistence *context*

[Bobby Anderson]

This is great, thank you. I have one last question.

How do you get a persistence context (entity manager) when you have a persistence unit (entity manager factory)?

I.E.
I define a persistence unit in my persistence.xml file named myPU. How do I inject that?

   
@PersistenceContext(unitName = "myPU")
private EntityManager em; 

Seems like I have seen that example before, but it seems incorrect if in fact myPU is a EntityManagerFactory (persistence unit) and not a EntityManager (persistence context).

Thanks again!

[Jaikiran Pai]

The injection code you posted is correct.

Billy Newman wrote:
Seems like I have seen that example before, but it seems incorrect if in fact myPU is a EntityManagerFactory (persistence unit) and not a EntityManager (persistence context).

That piece of injection code can be read as "inject a persistence context (entity manager), corresponding to a persistence unit (entity manager factory) named myPU".