transaction commit rollback

[daniele4]

Hi,
In my applications I use Seam managed transaction and it's work very well.
I some case after the commit on the db i must invoke a webservices but  How can I manage rollback? If somethings goes wrong i dont want call the webservices!!

Example:

public void save(){

em.persist(..);
web.callWebService();

}

[cash1981]

You are already doing it.

if persist fails exception is thrown and the next line is not executed.

[daniele4]

You are right Shervin!

I have another question!
If I undederstood right the data are stored on db only at the end of the method save(); suppose the webservices  web.callWebService() need the that same data, it could get from the db the old version of data!! right?
How can i force the commit or manager the transacrion manually?

public void save(){

em.persist(anagrafica);
web.callWebService();

}

@WebSevice(..
public void callWebService(){
  em.find(anagrafica);

}

thanks in advance

[cash1981]

You can try to manually flush after persist.

em.persist(obj);
em.flush();

[daniele4]

I tried but it doesnt work; i think because the webservices execute in a different context (other applicatio server).

I think should be possible manager the transaction manually, but i didnt found any documentation about that!!
any ideas?

[cash1981]

Your webservice gets old data? Is that the problem?

What is exactly the problem?

em.persist(obj);
em.flush();
web.callWebService();

does not work?

[cash1981]

daniele campanini wrote on Aug 04, 2010 04:27:


I think should be possible manager the transaction manually, but i didnt found any documentation about that!!
any ideas?

How you are injecting the EntityManager? If you are using Seam managed entityManager, I guess you are using @In?
Try using @PersistenceContext instead. I believe then that Seam will not manage the entityManager and you can manually control it.

Another way is by using a long-running conversation. Then in your @Begin you can write

@Begin(flushMode=FlushMode.MANUAL) 

Then nothing will be saved until you manually write flush();

[daniele4]

The exact problem is the inconsistency on the data.


When the webservice get the data  from the db, it isnt't updated!! It's difficult to explain so I write a example more detailed.


Case 1

public void save(){

User user = em.find(User.class, "name1")
user.setSurname("newsurname");  
em.merge(user);
em.flush();

User user2 = em.find(User.class, "name1")
System.out.println("Surname is " + user2.getSurname());

}

it print; Surname is newsurname

Case 2


public void save(){

User user = em.find(User.class, "name1")
user.setSurname("newsurname");  
em.persist(user);
em.flush();

web.callWebService();

}

public void callWebService(){
User user2 = em.find(User.class, "name1")
System.out.println("Surname is " + user2.getSurname());

}

it print; Surname is oldsurname

The transaction begin when the method save() is invoked and the commit is at the end of the method; so the data are persisted on the db
after the webservices is invoked. the flush() should store the data in the hibernate cache (not on the db) so the webservice which run on other server cannot get the updated data!!


I should do something like that;

public void save(){
--> Begin transaction

User user = em.find(User.class, "name1")
user.setSurname("newsurname");  
em.persist(user);
em.flush();

--> commit transaction

web.callWebService();

}


So the question is: how can i begin and commit a transaction manually?

I tried the example above so i am sure about the problem, I hope my considerations are correct too!!

thanks for your time Shervin

[cash1981]

I see.

The problem might be in the find method. I don't know how you have setup your application, but if second-level cache is enabled, then find will go and ask the second level cache, thus not hit the database.
You can try replacing the find with a manual query. It might work.

Do you see in the logs when you flush that insert is happening?

[daniele4]

In the logs I see the insert when the flush() in invoked but the data are in the db only at the end of save() method.
To test the behavior I run the application in debug mode with a breakpoint after the flush, if i execute a query at that point with a sql editor (select surname from user) the result is still oldsurname!!

[cash1981]

I see.

Ok then do this:

@RaiseEvent("saved")
public String save() {
   //stuff
   em.persist();
}

@Observer("saved")
public void goWebservice() {
   //Call webservice
}

If save() returns null or throws exception event is not raised.

[daniele4]

I am sure it work and i'll use it, but i think it's a workaround so i'd like to understand how to manager a transaction manually.

Something like:

em.getTransaction().begin()

em.getTransaction().commit()

thanks a lot for your patience, you are really skilled!

[daniele4]

Just tried your suggest, it doesnt work. I think the commit is after the method goWebservice().

[cash1981]

Very strange.
Perhaps you have enabled some strange caching which always asks the cache. Maybe your persist does not directly update the cache. Maybe there is a delay.

Try putting the @Observer method in another Seam component so that the code is not in the same component.

[daniele4]

I maybe found a solution..hope no extra problem :-)


@Stateful
@Scope(ScopeType.SESSION)
@TransactionManagement(TransactionManagementType.BEAN)
@Name("testBean")
public class TestBean implements ITestBean{

  @PersistenceContext(type = PersistenceContextType.TRANSACTION)
  private EntityManager em;
   
  @Resource
  private SessionContext sctx;
   
  ..


   public void save() throws Exception{
       javax.transaction.UserTransaction ut = sctx.getUserTransaction();
      
       ut.begin();
       //persist

       ut.commit();
       //call webservice

   }

}