Re: re-fething object from the database

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Fri Apr 28 2006 - 08:37:50 EDT

  • Next message: Andrus Adamchik: "Re: caching persistent objects"

    On Apr 28, 2006, at 3:55 AM, Marcin Skladaniec wrote:

    > Hello
    >
    > I have two contexts containing the same entity.
    > - one contains the list of all entities of this type - ListContext
    > - second contains only one entity for editing - EditContext
    >
    > I would like to notify the relevant context(s) when the object
    > changes, so it needs to be refreshed.

    Hmm... If those two contexts use the same ClientChannel,
    synchronization should be automatic. Of course it only happens on
    commit.

    > How can I do it ? I thought there was a notification mechanism in
    > 3t-cayenne, but I cant find a word about it anymore.

    The even mechanism was simplified (you may say downgraded) compared
    to the earlier version. I need to updated the docs. You can listen to
    the ClientChannel events. To register a listener implement
    DataChannelListener and use EventUtil class to register it.

    If you need to receive ongoing object events (i.e. property changes
    that by themselves do not result in commit), you can subclass
    CayenneContext and override 'propertyChanged'

    > What is the best way to force object to be re-faulted from
    > database ? I tried to set persistence state to hollow but it does
    > not work.

    Yeah, unfortunately client invalidate functionality didn't make it to
    1.2. One way to work around this is an explicit refresh query:

    Query q = new ObjectIdQuery(oid, false, ObjectIdQuery.CACHE_REFRESH)

    Andrus



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