Re: Evaluating Cayenne for Java Client application

From: Marek Wawrzyczny (mare..sh.com.au)
Date: Tue Nov 30 2004 - 18:33:30 EST

  • Next message: Mike Kienenberger: "Re: Evaluating Cayenne for Java Client application"

    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



    This archive was generated by hypermail 2.0.0 : Tue Nov 30 2004 - 18:33:42 EST