What is the best practice to handle JPA methods in JSF app?

Question

I am building a JSF-JPA web app(No EJB).
I have several methods that has JPA QL inside.
Because I have to put those methods inside JSF beans to inject EntityManagerFactory (am I right about this?).
And I do want to separate those methods from regular JSF beans which are used by page authors.
And I may need to use them in different JSF managed beans.
My question here is that what is the best practice to handle that?
I. write a or a few separate JSF Beans and inject them into regular Beans?
II. write a or a few separate JSF Beans and access them into regular Beans using FacesContext?
III. others?
Waiting to hear from you opinions.

Answer 1

You can create named queries on your Entities themselves then just call entityMgr.createNamedQuery("nameOfQuery");
Normally, we put these named queries in the class of the entity which will be returned. This allows for all information pertaining to a given entity and all ways of accessing that entity (except em.find() and stuff, of course) to be in one place. As long as the entity is defined in your persistence.xml file, any named queries which reside on that entity will be available through the EntityManager.
As for the EntityManagerFactory, we normally create an application scope bean which holds the factory itself (because this is a heavy-weight object) and then just get all EntityManager instances from that by injecting this bean into whatever needs it. For example, I might have:
//emfBB is the injected app scope bean which holds the entity manager factory.
private EmfBB emfBB;
private void lookupSomeData()
EntityManager em = this.getEmfBB().getEmf()
I hope this answered your question?
~Zack
Edited by: zmarr on Nov 6, 2008 1:29 PM