Configuring an EJB 3.0 Transaction Attribute

To configure how the container manages transactions when a client invokes a method of an EJB 3.0 enterprise bean configured for container-managed transactions, you can use annotations (see Using Annotations) or deployment XML (see "Using Deployment XML").

For more information, see the following:

• "Who Manages a Transaction?"

• "What are Container-Managed Transactions?"

• "How are Transactions Handled When a Client Invokes a Business Method?".

Using Annotations

You can configure transaction management using the @TransactionAttribute annotation attribute value, as Example 21-2 shows. Table 21-1 lists the TransactionAttributeType values you can specify and shows how the container will respond depending on whether or not a client-controlled transaction exists at the time the method is invoked.

Table 21-1 TransactionAttributeType Values for @TransactionAttribute

Transaction Attribute	Client-Controlled Transaction Exists	Client-Controlled Transaction Does Not Exist
NOT_SUPPORTED	Container suspends client transaction	Use no transaction
SUPPORTS	Use client-controlled transaction	Use no transaction
REQUIREDFoot 1	Use client-controlled transaction	Container starts a new transaction
REQUIRES_NEW	Use client-controlled transaction	Container starts a new transaction
MANDATORY	Use client-controlled transaction	Exception raised
NEVER	Exception raised	Use no transaction

^Footnote 1 Default.

You can apply the @TransactionAttribute annotation at the class-level to specify the default transaction attribute for all business methods of the enterprise bean. You can apply this annotation at the method-level to specify the transaction attribute for that method. Applying the annotation at the method-level overrides the class-level annotation (if any) for that method.

Example 21-2 Configuring Transaction Attribute for an EJB 3.0 Session Bean

import javax.ejb.Stateful;
import javax.annotation.PostConstruct;
import javax.ejb.Remove;
import javax.ejb.TransactionManagement;
import javax.ejb.TransactionManagementType;
import javax.ejb.TransactionAttribute;
import static javax.ejb.TransactionAttributeType.REQUIRED;
import static javax.ejb.TransactionAttributeType.REQUIRES_NEW;
import com.acme.Cart;

@Stateful
@TransactionManagement(value=TransactionManagementType.CONTAINER)
@TransactionAttribute(value=REQUIRED)
public class CartBean implements Cart {
    private ArrayList items;

    @PostConstruct
    public void initialize() {
        items = new ArrayList();
    }

    @Remove
    @TransactionAttribute(value=REQUIRES_NEW)
    public void finishedShipping() {
        // Release any resources.
    }

    public void addItem(String item) {
        items.add(item);
    }

    public void removeItem(String item) {
        items.remove(item);
    }
}

Using Deployment XML

For an EJB 3.0 enterprise bean, you configure transaction attributes in the orion-ejb-jar.xml file as you would for an EJB 2.1 enterprise bean (see "Using Deployment XML").