Re: Setting a user stamp on objects

From: Derek Rendall (cayenn..sure.com)
Date: Mon Dec 06 2004 - 17:37:53 EST

  • Next message: Mike Kienenberger: "DataContext subclassing [was: Re: Setting a user stamp on objects]"

    > Yeah, that's a pretty common situation when you have to populate some
    > DataObject properties with external data (i.e. data not available within
    > DataObject itself) in certain points of the object lifecycle. I think
    > having a subclass of DataContext is entirely reasonable.

    The only concern I have about the subclassing is the EventSubject static
    variables:
        // DataContext events
        public static final EventSubject WILL_COMMIT = EventSubject.getSubject(
                DataContext.class,
                "DataContextWillCommit");
        public static final EventSubject DID_COMMIT = EventSubject.getSubject(
                DataContext.class,
                "DataContextDidCommit");
        public static final EventSubject DID_ROLLBACK = EventSubject.getSubject(
                DataContext.class,
                "DataContextDidRollback");

    They use the DataContext class, so I was wondering if thats going to
    adversely affect anything if I am using my DataContext subclass everywhere?
    If thats a non-issue, then I'll gladly switch to a subclass.

    > Re: "WILL_COMMIT". I guess in the meantime we need to fix that and fire it
    > prior to validation (could someone please open an issue in Jira?) On the
    > long run we need to think of a big picture for DataObject lifecycle and

    Actually, I think firing after validation makes perfect sense. I can imagine
    times when I want to know that a commit is going to happen before I do
    something special. If validation hasnt occurred yet, then there is a chance
    that we won't actually proceed with the commit. I think that it would be
    better to have another event that was generated before validation, e.g.
    "STARTING_COMMIT_PROCESS" (or something better :-). However, it may be
    better to delay that until the "big picture" becomes clearer :-)

    Thanks

    Derek



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