Java Reference
In-Depth Information
Session bean class
A stateless session bean is just a Java class annotated with the annotation
@Stateless .
@Stateless(name = "EJB3SessionEJB",
mappedName = "EJB3RelationshipsJSF-Model-EJB3SessionEJB")
The mappedName element specifies the mapped name for the session bean. The
mappedName is used in the JNDI lookup of the session bean from a client. The @
Remote annotation indicates that the class implements a remote interface:
public class EJB3SessionEJBBean implements EJB3SessionEJB {
We shall be using an EntityManager for database persistence. Inject an
EntityManager using dependency injection:
@PersistenceContext(unitName = "em")
private EntityManager em;
Add getAll<> methods to retrieve all Edition entities, all Section entities, and
all Article entities. By default, container-managed transactions do not require
individual methods to be associated with transactions. Methods may be associated
with transactions using the transaction attributes. Associate each of the getAll
methods with a transaction attribute with TransactionAttributeType set to
REQUIRES_NEW , which implies that a new transaction is required each time the
method is invoked:
In each of the getAll<> methods, find all entities using the named query to find
all entities. The getAll<> methods return a parameterized List . For example, the
getAllEdtions method returns List<Edition> . In the getAllEditions method,
create an ArrayList<Edition> type variable:
ArrayList<Edition> editions = new ArrayList<Edition>();
Create a Query object for the named query findEditionsAll , which was defined
in the Edition entity class. A Query object is created using the createNamedQuery
method of the EntityManager object that was created using dependency injection:
Query q = em.createNamedQuery("findEditionsAll");
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