Interesting question! I don't have any experience in doing this but it made me search in one of my Websphere book. Not sure if that would fulfill your requirements but TRANSACTION_SERIALIZABLE and PessimisticUpdate-Exclusive might be worth investigating. I am not sure what container you use and if JTA is available to you. I would check the JDBC driver as well, it might have some extra transaction support. Writing your own is probably pretty tempting when the answer is not obvious and you would know how it works. On the other side you have an extra write (at least) each time and need to manage the lock if the transaction is abandoned.
If you have the time to investigate more, you'll probably a transaction guru soon. We, developers, have a tendency to avoid transactions and isolation levels like plague... Not easy development and test subjects as the lack of answers indicates... Good luck and let us know what solution you end up with, I am curious. Fred On 2/20/07, Murray Collingwood <[EMAIL PROTECTED]> wrote:
James Carman <james <at> carmanconsulting.com> writes: > You can use optimistic locking. When the user submits and they have > outdated data, then you just merge the object's data with what is in > the data store and show it back to the user for them to confirm it. In an application where the user can spend 20 minutes completing the information in a row, they are not going to be happy when they find out somebody else has been updating this same row and the information has all been merged. They then spend another 10 minutes cleaning up all of the duplicated changes. Even pessimistic locking is not sufficient. I need guaranteed write-exclusive locking for the duration of the request. ie when I read-for-update the record should be locked against all other read-for-update requests until I save my changes and release the lock. It sounds as though I'm going to have to write my own...again. Cheers mc --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
