Accessing the EntityManager from a non-EJB class

[ceracm]

EJBs can obtain a reference to an EntityManager through dependency injection. But how can a non-EJB class called by an EJB access the EntityManager?

Is it simply a matter of using JNDI code like this?

EntityManager em = (EntityManager) new InitialContext()
 .lookup("java:comp.ejb3/env/EntityManager");

This works in preview 5 but is legal and does it perform well?

Thanks

Chris

[kabirkhan]

It is fine (apart from possible philosophical discussions :-)

Note that the spec mentions the EntityManager should be bound under java:comp/env/EntityManager. We are using java:comp.ejb3/env/EntityManage while waiting for the spec to be completed.

[ceracm]

Thanks.

What theoretical discussions do you have in mind?

I think its reasonable for a non-EJB to call the EntityManager. For example, if you want to implement a DAO-like class that is called by the session bean.

It would be nice if a DAO could use dependency injection as well but I assume that it would be too inefficient to make the DAO a session bean as well.

[epbernard]

"ceracm" wrote:
I assume that it would be too inefficient to make the DAO a session bean as well.

Why?

[ceracm]

"epbernard" wrote:

"ceracm" wrote:
I assume that it would be too inefficient to make the DAO a session bean as well.

Why?

Thats a very good question.
One that is perhaps best answered by an application server developer

I would imagine that calling a session bean through a local interface from another session bean has some overhead.

But I suppose you could argue that the overhead of the is negligible compared to the work being done by the DAO.

Comments?