[JBoss-user] [EJB/JBoss] - Re: NoSuchObjectLocalException
What is your container configuration. Are you using Instance Per Transaction ?? and what is the lock ? Raghu View the original post : http://www.jboss.org/index.html?module=bbop=viewtopicp=3830906#3830906 Reply to the post : http://www.jboss.org/index.html?module=bbop=postingmode=replyp=3830906 --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470alloc_id=3638op=click ___ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
[JBoss-user] [EJB/JBoss] - Re: NoSuchObjectLocalException
Hi,
If your session bean is declared as Container-managed transactions, your problem
seems as a JBoss bug.
Perhaps try to set transaction-type to Bean, and then create a user transaction within
your addAttendance method.
The user transaction can be obtain with:
| try {
| ctx = new InitialContext();
| tx = (UserTransaction)ctx.lookup(UserTransaction);
| tx.begin();
| ...
| tx.commit();
| } catch (Exception e)
| ...
| tx.rollback();
| }
|
| ctx.close();
|
I'm not sure you can obtain a transaction with
sessionContext.getUserTransaction(); in this case.
Good luck ;-)
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[JBoss-user] [EJB/JBoss] - Re: NoSuchObjectLocalException
Hi, I guess this is valid behaviour as if you have two threads accessing the same entity bean with one deleting the row in the database, the other is bound to recieve the exception. Transaction behavior won't help as its not an exclusive usage of the entity bean instance. Transaction only helps for atomicity of operation. Hope this helps View the original post : http://www.jboss.org/index.html?module=bbop=viewtopicp=3830435#3830435 Reply to the post : http://www.jboss.org/index.html?module=bbop=postingmode=replyp=3830435 --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470alloc_id=3638op=click ___ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
[JBoss-user] [EJB/JBoss] - Re: NoSuchObjectLocalException
Hello Vikas, Thanks for replying. I am kind scared that this will be a valid behaviour because if I am executing a findBy method that is NOT read-only and has a transaction type Required then I better have the lock to do whatever I want with that bean. Nobody can do a findBy... on the same bean unless I am done with it first. Isn't this the appropiate behaviour? In the logs, I can see that two different threads are executing the same findBy... method of an entity bean which is kind of scary because if one thread decides to delete the record then the other one will have a primary key that doesn't exist anymore in the database. There has to be a way to avoid this confrontation between these two beans. How come the second thread is being allow to execute the findBy... method in the first place? Thanks in advance, jchang P.S. Please let me know if I am missing something? View the original post : http://www.jboss.org/index.html?module=bbop=viewtopicp=3830447#3830447 Reply to the post : http://www.jboss.org/index.html?module=bbop=postingmode=replyp=3830447 --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470alloc_id=3638op=click ___ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
[JBoss-user] [EJB/JBoss] - Re: NoSuchObjectLocalException
Your problem is not a part of EJB or whatever specification. Having a thread deleting rows while another list the rows is a business problem. The whole solution for handling that is a combination of transaction, reentrance and lock mechanism. The lock mechanism is not a part of EJB spec, but application servers can do that. You can also write a portable lock mechanism, which is decribed at the location: [url] http://www.javaworld.com/javaworld/jw-07-2001/jw-0713-optimism.html [/url] I hope this helps you. View the original post : http://www.jboss.org/index.html?module=bbop=viewtopicp=3830452#3830452 Reply to the post : http://www.jboss.org/index.html?module=bbop=postingmode=replyp=3830452 --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470alloc_id=3638op=click ___ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
[JBoss-user] [EJB/JBoss] - Re: NoSuchObjectLocalException
Hello Sesques.
I appreciate your help.
Here is a snippet of code. As you can see, the addAttendance of this STATELESS bean
is calling the findAttendance method with an specific memberId and timeSlotId. In the
logs, I can see that two threads are calling this method almost at the same time but
the first thread get to the deleteAttendance method and remove the record from the db.
Meanwhile, the second thread went into a waiting state because the first one is
working within a transaction. But when it wakes up, it tries to execute code based on
the primary keys that got from the findByMemberAndTimeSlotId method that is part of
the findAttendance method.
I am still confused why the container lets 2 threads execute the
findByMemberAndTimeSlotId concurrently the first time.
By the way, the entity bean has transaction type Required and the finder methods are
NOT read-only. The only methods that are read-only are the get methods. And the
commit-option is A
/**
|* @ejb.interface-method
|*
|* @ejb.transaction
|*type=Required
|*/
| public void addAttendance(String inConferenceId, String inMemberId, String
inGroupId, String inTimeSlotId)
| {
| ...code...
|
| // get the record for the current time slot
| attendanceMain = findAttendance(inMemberId, inTimeSlotId);
|
| ...more code...
|
| // delete the existing attendance record
| deleteAttendance(attendanceMain);
|
| ...more code...
| }
|
|
| /**
|* @ejb.interface-method
|*
|* @ejb.transaction
|*type=Required
|*/
|
| public AttendanceVO findAttendance(String inMemberId, String inTimeSlotId)
| {
| AttendanceVO retval = null;
| logger.debug(findAttendance invoked);
| try
| {
| AttendanceLocalHome alh = AttendanceUtil.getLocalHome();
| AttendanceLocal al = alh.findByMemberAndTimeSlotId(inMemberId,
inTimeSlotId); //second thread gets into a wait state while the first one is doing
transactional process.
| retval = al.getAttendanceVO(); //pk for attendance is gone at this point,
exception get thrown here
| }
| catch (FinderException fe)
| {
| logger.debug(fe.getMessage());
| }
| catch (NamingException ne)
| {
| logger.warn(ne.getMessage(),ne);
| }
| return retval;
| }
|
|
| /**
|* @ejb.interface-method
|*
|* @ejb.transaction
|*type=Required
|*/
| public boolean deleteAttendance(AttendanceVO inAttendance)
| {
| boolean retval = false;
| if (inAttendance != null)
| {
| try
| {
| AttendanceLocalHome alh = AttendanceUtil.getLocalHome();
| AttendanceLocal al = alh.findByPrimaryKey(inAttendance.getId());
| if (al != null)
| {
| try
| {
| al.remove();
| retval = true;
| }
| catch (RemoveException re)
| {
| logger.warn(re.getMessage());
| }
| }
| }
| catch (FinderException fe)
| {
| logger.warn(fe.getMessage());
| }
| catch (NamingException ne)
| {
| logger.warn(ne.getMessage(),ne);
| }
| }
| return retval;
| }
|
Thanks for the help
jchang
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