8.4. Using the JPA "delegate"
The EntityManager interface lets you access a vendor-specific API via the getDelegate() method. Naturally, the most interesting vendor is Hibernate, and the most powerful delegate interface is org.hibernate.Session. You'd be nuts to use anything else. Trust me, I'm not biased at all.
But regardless of whether you're using Hibernate (genius!) or something else (masochist, or just not very bright), you'll almost certainly want to use the delegate in your Seam components from time to time. One approach would be the following:
@In EntityManager entityManager;
@Create
public void init() {
( (Session) entityManager.getDelegate() ).enableFilter("currentVersions");
}
But typecasts are unquestionably the ugliest syntax in the Java language, so most people avoid them whenever possible. Here's a different way to get at the delegate. First, add the following line to components.xml:
<factory name="session"
scope="STATELESS"
auto-create="true"
value="#{entityManager.delegate}"/>
Now we can inject the session directly:
@In Session session;
@Create
public void init() {
session.enableFilter("currentVersions");
}
