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 context where
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.
===========================================================================
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff
JSP-INTEREST".
For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST
DIGEST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
===========================================================================
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
For digest: mailto [EMAIL PROTECTED] with body: "set JSP-INTEREST DIGEST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
