Have you posted this to the EJB list?
I know this was discussed on EJB quite a while ago, I just don't
remember the outcome. However, you might want to move the question
there and see what those list members have to say on the mattter -
----- Original Message -----
From: Keith Kwiatek <[EMAIL PROTECTED]>
Date: Thursday, April 5, 2001 8:37 am
Subject: Re: Record-locking in J2EE/JSP/Servlet apps?
> I think you mean "any time you want to work pessimistically" ....
>
> This is an outstanding issue.... I have also been wrestling with
> the same
> thing for a while now.... and it seems, for now, that the kludgy
> timestampmethod is about the only solution.... I saw some more
> discussion on this
> issue on www.theserverside.com about this very issue, but I
> forget exactly
> where on the web site....
>
> EJB doesn't address "pessimistic" row level locking in a stateless
> environment --BUT IT SHOULD! EJB must address this issue at some
> point... it
> is such a basic requirment! The whole idea of the J2EE is to
> provide a
> framework of basic utilities shared by applications.
>
> Keith
>
> ----- Original Message -----
> From: "Jonathan Goldberg" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Wednesday, April 04, 2001 11:07 PM
> Subject: Re: Record-locking in J2EE/JSP/Servlet apps?
>
>
> > Hi Bill
> >
> > I don't know that this problem is specific to JSP, and
> > I don't know if EJB solves the problem automatically.
> >
> > Basically, any time you want to work optimistically, you
> > will need to verify that the data you are trying to update
> > is the data you retrieved. One manual strategy is to add
> > a timestamp to the table(s), and do something like:
> >
> > {
> > retrieve data without transaction
> > display data to user
> > }
> >
> > later on
> > {
> > get data sent by user
> > open transaction
> > retrieve data from database
> > compare timestamps
> > if same then
> > {
> > update data with user database
> > update timestamps
> > commit transaction
> > send OK confirmation to user
> > }
> > else
> > {
> > rollback transaction
> > send new data and error message to user
> > }
> > }
> >
> > Hope this helps
> >
> > Jonathan
> >
> > ==========================================
> > Jonathan Goldberg 8, HaP'nina Street
> > Amdocs (Israel) Ra'anana, 43000, Israel
> > +972-9-7762071 (work) +972-9-7763800 (fax)
> > mailto:[EMAIL PROTECTED]
> >
> >
> > -----Original Message-----
> > From: Hines, Bill [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, April 04, 2001 9:44 PM
> > To: [EMAIL PROTECTED]
> > Subject: Record-locking in J2EE/JSP/Servlet apps?
> >
> >
> > How are any of you solving the problem in the stateless webapp
> contextwhere
> > two users pull up the same record from a database in a JSP page,
> and user
> > one changes the address and saves but then user two, who has the old
> address
> > on his JSP page, changes the phone number and hence over-writes
> user one's
> > address change? Are you locking the record in the back-end
> database and
> then
> > implementing the SessionBindingListener to release it when the
> session> expires, if the user leaves the webapp without logging
> out? Does EJB solve
> > this problem? I'd like to hear the solutions that are out there.
> >
> >
>
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