Re: Evaluating Cayenne for Java Client application

From: Marek Wawrzyczny (mare..sh.com.au)
Date: Tue Nov 30 2004 - 17:58:23 EST

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

    Hi,

    Following Andrus' lead I've taken this to cayenne-user.

    The reason pessimistic lock is preferred is that we are writing an
    application where record modifications are going to be frequent. The
    users are VERY non-technical. Optimistic locking offers only the
    following three solutions to conflicts as far as I can see:

    1) Replace someone else's changes with the user's changes.
    2) Prevent changes being saved.
    3) Present the user with an interface to choose the correct data.

    We don't think the users of this particular system could cope with any
    of these choices.

    On 01/12/2004, at 02:05, Gentry, Michael wrote:

    > Cayenne, with release 1.1, supports optimistic locking (like EOF). I
    > don't know of any pessimistic locking support currently built into
    > Cayenne (or planned), but Andrus or Mike or someone would be better
    > informed than myself.
    >
    > Is there a reason you require pessimistic locking over optimistic
    > locking?
    >
    > Thanks,
    >
    > /dev/mrg
    >
    > -----Original Message-----
    > From: Marek Wawrzyczny [mailto:mare..sh.com.au]
    > Sent: Monday, November 29, 2004 10:12 PM
    > To: cayenne-deve..bjectstyle.org
    > Subject: Evaluating Cayenne for Java Client application
    >
    >
    > Hi all,
    >
    > We have just started evaluating Cayenne for a multi-user Java Client
    > application.
    >
    > 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?
    >
    > The second question I have is about distribution of persistence across
    > a server client solution. Server talks to the data source and holds all
    > of business logic for the enterprise objects, clients communicate
    > exclusively with the server across the network and have only some of
    > the business logic for enterprise objects, mostly display and
    > validation logic. All pretty much al a Apple's EOF. We would like to
    > implement pessimistic locking on the server end.
    >
    > Is this possible at present with Cayenne? If not, will this be possible
    > in the future? Finally, perhaps someone has already implemented this
    > functionality and would be prepared to share their work?
    >
    > Your time is much appreciated.
    >
    > Cheers,
    >
    >
    > Marek Wawrzyczny

    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 - 17:58:41 EST