On 01/12/2004, at 03:02, Mike Kienenberger wrote:
> Marek Wawrzyczny <mare..sh.com.au> wrote:
>> We have hit the first wall, pessimistic locking. For some reason I
>> have
>> been under the impression that Cayenne supports pessimistic locking
>> but
>> somehow I cannot find any reference to it in the examples, FAQs or
>> JavaDocs, perhaps I am looking in the wrong place. Can someone point
>> me
>> in the right direction?
>
> It's not there yet. Patches are welcome :) New features in cayenne
> tend to
> get started by those who need them. But that's not to say that you'd
> have
> to do it all by yourself.
>
> I'm no database layer expert, but I managed to create the basic patch
> for
> optimistic locking that's now the basis for optimistic locking in
> Cayenne,
> so I think you'll find it easy to contribute. The infrastructure
> support
> for specifying locking in the model is already there. You'd just
> need to
> implement the details specific to performing pessimistic locking. I've
> never used pessimistic locking in an EOF/Cayenne environment, so I'm
> not
> sure how you'd want it to work. Optimistic locking was probably a
> little
> easier since it just modifies the qualifier on update statements.
>
> The best way to get started is to throw out a general concept of how
> you'd
> see it working on the dev list, and you'll either get some design
> refinement
> suggestions or get pointed to the right places to start implementing
> it.
>
> -Mike
Sounds intriguing, I will have a look at home if this is not way over
my head. I do remember however that pessimistic locking is database
dependant, I presume this is detectable/done through the JDBC?
Of course I can't do any of this at work, and at home - not after
Xmas... hopefully by then I'll have Internet access form outside of
work.
Marek Wawrzyczny
software engineer
-------------------------->
ish group pty ltd
http://www.ish.com.au
7 Darghan St Glebe 2037 Australia
phone +61 2 9660 1400 fax +61 2 9660 7400
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