Building an EJB 3.0 Persistence Model with Oracle JDeveloper - EJB 3.0 Database Persistence with Oracle Fusion Middleware 11g - page 93

The CatalogTestSessionEJBBean class is annotated with the annotation
@Stateless . The mappedName attribute specifies the global JNDI for the session
bean. We shall use the mapped name in the test client to lookup the session bean and
invoke method/s on it. The @Remote annotation indicates that the session bean is a
remote interface.
@Stateless(name = "CatalogTestSessionEJB", mappedName = "EJB3-
SessionEJB")
@Remote
public class CatalogTestSessionEJBBean implements
CatalogTestSessionEJB { }
In the session bean an EntityManager is injected using the @PersistenceContext
annotation. The unitName is specified, but not required, as the EntityManager
variable name is the same as the persistence unit name.
@PersistenceContext(unitName = "em")
private EntityManager em;
Add a method test() to the session bean and the remote interface. In the test()
method, create a Catalog entity instance with the new operator:
Catalog catalog =new Catalog("Kimberly Floss", "Nov-Dec 2004", new
Integer(1),"Oracle Magazine", "Oracle Publishing","Database Resource
Manager");
Invoke the persistEntity(Object) method to persist the entity bean instance:
persistEntity(catalog);
The persistEntity method invokes the persist method of the EntityManager to
persist the entity bean:
em.persist(entity);
Similarly, persist two more entity bean instances. Next, create an instance of the
Query object using the createQuery method to run a Java Persistence Query
Language statement. Bind an author name to the named parameter :name using
the setParameter method, and run the Java persistence query statement using the
getResultList method, which returns a List :
List catalogEntry =
em.createQuery("SELECT c from Catalog c where
c.author=:name").setParameter("name","Jonas Jacobi").getResultList();
Iterate over the List , which is actually just one catalog entry, to output field values
for the journal , publisher , edition , title , and author fields:
for (Iterator iter = catalogEntry.iterator(); iter.hasNext(); )