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We have seen the usage of most of the EntityManagerFactory methods in listing 9.2. Perhaps the most interesting aspect of listing 9.2 is the entityManager. joinTransaction() call in the updateItem method. Let s discuss this method in a little more detail. As we hinted in the beginning of this section, unlike container-managed EntityManagers, application-managed EntityManagers do not automatically participate in an enclosing transaction. Instead, they must be asked to join an enclosing JTA transaction by calling the joinTransaction method. This method is specifically geared to using application-managed EntityManagers inside a container, where JTA transactions are usually available. Application-managed EntityManagers outside the Java EE container In Java SE environments, however, JTA is not a possibility. Resource-local transactions must be used in place of JTA for such environments. The EntityTransaction interface is designed with exactly this scenario in mind. We ll explore this interface by reimplementing the code to update an item from listing 9.2 for an SE application. Listing 9.3 also serves the dual purpose of being a good template for using application-managed EntityManagers without any help from the container.

With the annotation-based development style, a pointcut is a method with an empty body that is annotated with @Pointcut. This annotation takes the pointcut expression as a parameter. For example, the following code snippet defines the pointcut toBeTraced: @Pointcut( "call(* aop.aspectj.Order.*(..))" ) void toBeTraced() {} With this new style, the parameters that would have been defined for a pointcut are now defined as parameters of the annotated method.

EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("actionBazaar");

EJB home references implement the EJBHome interface, which declares a method getEJBMetaData(). This method returns an instance of the EJBMetaData class, which provides information about the EJB belonging to the home object. The Client class in listing 1.16 demonstrates how to use the EJBMetaData instance describing an EJB.

EntityManager entityManager = entityManagerFactory.createEntityManager(); try { EntityTransaction entityTransaction = entityManager.getTransaction(); entityTransaction.begin(); entityManager.persist(item); entityTransaction.commit(); } finally { entityManager.close(); entityManagerFactory.close(); }

The first thing that should strike you about listing 93 is the amount of boilerplate code involved to accomplish exactly the same thing as the updateItem method in listing 91 (cutting and pasting both code snippets into a visual editor and comparing the code side-by-side might be helpful in seeing the full picture at a glance) The javaxpersistencePersistence object s createEntityManagerFactory method used in listing 93 b is essentially a programmatic substitute for the @PersistenceUnit annotation The single parameter of the createEntityManagerFactory method is the name of the EntityManagerFactory defined in the persistencexml deployment descriptor Since the container is no longer helping us out, it is now important to be sure to close the EntityManagerFactory returned by the createEntityManagerFactory method when we are done, in addition to closing the EntityManager H Just as in listing 9.

public class Client { private String url; private String symbol; private String description; private EJBHome home;

Advice code blocks are already blocks of instructions, so it is quite natural that advice code blocks are now methods. Five new annotations are available, one for each different type of advice code: @Before, @After, @AfterReturning, @AfterThrowing, and @Around. In all five cases, the annotation takes the associated pointcut expression as a parameter. Before Advice Code The following code snippet illustrates the definition of before advice: @Before( "toBeTraced()" ) public void beforeTrace() { ... } Note that with this new development style, advice code blocks now share the same name as the method. If the before advice code needs to access the joinpoint, a parameter of type JoinPoint is added to the method signature, as shown here:

2, the EntityManagerFactory s createEntityManager method is used to create the application-managed EntityManager C However, before merging the Item entity to the database F, we now create an EntityTransaction by calling the getTransaction method of the EntityManager D The EntityTransaction is essentially a high-level abstraction over a resourcelocal JDBC transaction, as opposed to the distributed JTA transaction we joined in listing 92 At first it is natural to think that a joinTransaction call is still necessary to make the EntityManager aware of the enclosing transaction Remember that since the EntityManager itself is creating the transaction instead of the container, it implicitly keeps track of EntityTransactions, so the join is not necessary The rest of the transaction code the begin E and the commit G do exactly what you d expect As might be obvious, the EntityTransaction interface also has a rollback method to abort the transaction.