EJB Transactions

Question

I am developing a Web Service using a Stateless EJB, which has a single entry point (method). This method has 3 steps and I want step 1 to occur in a different transaction than steps 2 and 3 (which should be in the same transaction). These "steps" consist in callings to injected Stateless EJBs. Let me explain with some code:

@Stateless  
@WebService(...)  
public class MyWebServiceImpl implements MyWebService { 

     @EJB  
     private UserBusinessBean userBusinessBean;  

     @EJB  
     private EventsBusinessBean eventsBusinessBean;  

     @WebMethod(...)  
     public MyWebServiceResult process(MyWebServiceParam param) {  
          // extract data from param  
          EventResult createEventResult = eventsBusinessBean.createEvent(data); // step 1  
          // do some extra processing  
          User user = userBusinessBean.createUser(someData); // step 2  
          // do some extra processing  
          EventResult updateEventResult = eventsBusinessBean.updateEvent(moreData); // step 3  
     }  
}  

The 2 injected EJBs are themselves Stateless and have injected references to Stateless DAOs, whose function is to call stored procedures on the database.

I need to have step 1 executing in one transaction and steps 2 and 3 executing in another transaction (because if step 2 or 3 fails, the info from step 1 is already committed).

I know I have 2 options to implement this: container-manager transactions or user-managed transactions. I believe the former approach is more safe than the latter, delegating the management to the container (in my case, a Weblogic server). But I can't understand how I should use the EJB Transactions Annotations to implement this logic. Should I annotate the methods from my injected Business Beans? And what about the DAOs, do they need to have annotations too? And which ones should I use?

I hope you can give me some help in this one. Let me know if you need to know more details from my implementation.

Answer 1

Because MyWebServiceImpl is an @Stateless , it will implicitly have a REQUIRED transaction attribute. To ensure step 1 is completed in its own transaction, you should add @TransactionAttribute(REQUIRES_NEW) to the EventsBusinessBean.createBean method. That will cause the bean to be created in its own transaction, and then the remaining actions in process will operate within another transaction.