John,
Here is the offending class, compliments of the Sun Blueprint team:
public class ShoppingClientControllerWebImpl implements WebClientController
{
private ShoppingClientControllerLocal sccEjb;
private HttpSession session;
public ShoppingClientControllerWebImpl() {
}
// ... stuff...
//
// the important bit ...
public synchronized EventResponse handleEvent(Event ev)
throws EventException {
return sccEjb.processEvent(ev);
}
}
So you see that the webcontroller is the _only_ access to the sfsb. And the
only call is synchronized, thus preventing cocurrent calls to the stateful
session bean.
regards,
the elephantwalker
www.elephantwalker.com
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of
[EMAIL PROTECTED]
Sent: Wednesday, March 20, 2002 12:05 PM
To: Orion-Interest
Subject: RE: Concurrent calls to Session bean methods
I haven't seen the history on this issue, but it interests me. I had a
quick look at the ShoppingClientControllerEJB class that is given as an
example by Sun in the Session Facade design pattern, but couldn't see where
they are synchronizing calls. Can you provide some more clues?
Thanks,
John H.
"The elephantwalker"
<[EMAIL PROTECTED]> To:
[EMAIL PROTECTED]
Sent by: cc:
owner-orion-interest@orion Subject: RE:
Concurrent calls to Session bean methods
server.com
03/19/02 10:31 PM
Please respond to
Orion-Interest
Vani,
You can use the petstore trick. Use a facade class which sychronizes each
call to your session bean. That should do the trick.
This is a _famous_ problem with session beans.
regards,
the elephantwalker
www.elephantwalker.com
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Vani H.S.
Sent: Wednesday, March 20, 2002 12:04 AM
To: Orion-Interest
Subject: Concurrent calls to Session bean methods
Hello All,
I have been trying to deploy an application consisting of session beans
and mdbs onto orion1.5.4.
But I seem to run into deadlocks, because my session bean gets called
concurrently. Please can anybody can tell me if there is a setting to allow
concurrent calls so that, when a session bean method is called at one time,
the EJB container blocks the concurrent method call and allows it to
proceed
when the previous call has completed?
If not, how should this problem of concurrent calls be handled in orion?
Please help.
Thanks,
Vani
The allow-concurrent-calls element specifies whether a stateful session
bean
instance allows concurrent method calls. By default,
allows-concurrent-calls
is false. However, when this value is set to true, the EJB container blocks
the concurrent method call and allows it to proceed when the previous call
has completed.
_________________________________________________________________
Join the world's largest e-mail service with MSN Hotmail.
http://www.hotmail.com
