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Define container transactions for EJB modules

 

Container transaction properties specify how an Enterprise JavaBeans (EJB) container is to manage transaction scopes for the enterprise bean's method invocations. A transaction attribute is mapped to one or more methods. Some container transaction settings are not available for all enterprise beans. Also, some methods are not available for particular transaction settings and beans. These rules have been implemented in the Add Container Transaction wizard based on the EJB 1.1 and EJB 2.x specifications.

 

Overview

To add a container transaction to an enterprise bean:

 

Procedure

  1. In the Project Explorer view of the J2EE perspective, right-click the Deployment Descriptor for your EJB project and select Open With > Deployment Descriptor Editor to open the deployment descriptor editor.

  2. On the Assembly page of the editor, click Add in the Container Transactions section.

  3. Select one or more enterprise beans from the list of beans found.

  4. Select a container transaction type from the following choices:

    • NotSupported - Directs the container to invoke bean methods without a transaction context. If a client calls a bean method from within a transaction context, the container suspends the association between the transaction and the current thread before invoking the method on the enterprise bean instance. The container then resumes the suspended association when the method invocation returns. The suspended transaction context is not passed to any enterprise bean objects or resources that are used by this bean method.

    • Supports - Directs the container to invoke the bean method within a transaction context if the client calls the bean method within a transaction . If the client calls the bean method without a transaction context, the container calls the bean method without a transaction context. The transaction context is passed to any enterprise bean objects or resources that are used by this bean method.

    • Required - Directs the container to invoke the bean method within a transaction context. If a client calls a bean method from within a transaction context, the container calls the bean method within the client transaction context. If a client calls a bean method outside a transaction context, the container creates a new transaction context and calls the bean method from within that context. The transaction context is passed to any enterprise bean objects or resources that are used by this bean method.

    • RequiresNew - Directs the container to always invoke the bean method within a new transaction context, regardless of whether the client calls the method within or outside a transaction context. The transaction context is passed to any enterprise bean objects or resources that are used by this bean method.

    • Mandatory - Directs the container to always invoke the bean method within the transaction context associated with the client. If the client attempts to invoke the bean method without a transaction context, the container throws the javax.jts.TransactiononRequiredException exception to the client. The transaction context is passed to any EJB object or resource accessed by an enterprise bean method. EJB clients that access these entity beans must do so within an existing transaction . For other enterprise beans, the enterprise bean or bean method must implement the Bean Managed value or use the Required or Requires New value. For non-enterprise bean EJB clients, the client must invoke a transaction by using the javax.transaction.UserTransaction interface.

    • Never - Directs the container to invoke bean methods without a transaction context. If the client calls a bean method from within a transaction context, the container throws the java.rmi.RemoteException exception. If the client calls a bean method from outside a transaction context, the container behaves in the same way as if the Not Supported transaction attribute was set. The client must call the method without a transaction context

  5. Select one or more methods elements from the list.

  6. Click Finish.

 

Results

The container transaction is added and displayed in the Container Transactions section, where the container transactions are listed by container transaction type.

 

What to do next

After you define container transactions, you can use the deployment descriptor editor to work with them. Information about the editor can be found in the WAS Express documentation.



EJB containers

 

Related tasks


Assembling EJB modules