Hi Armin,
Thanks for the info!
Since I'm thinking of using my own ObjectCache implementation anyway (to
use hard rather than soft references), I wonder if it would make sense to
replace the collection attributes in the cache's cache() method. Pseudo
code:
for each CollectionDescriptor cod in ClassDescriptor cld for
myObject
{
coClass = cod.getCollectionClass();
if ( ! myObject.getTheCollection() instanceof coClass )
{
coInst = coClass.newInstance();
coInst.addAll(myObject.getTheCollection());
myObject.setTheCollection(coInst);
}
}
Would you see any obvious problems with this approach? On first glance it
seems this could/should be done in all caches that keep the references
across transaction boundaries.
Regards,
Gerhard
Armin Waibel <[EMAIL PROTECTED]>
14.10.2003 18:04
Bitte antworten an "OJB Users List"
An: OJB Users List <[EMAIL PROTECTED]>
Kopie:
Thema: Re: Initializing collection attributes
Hi Gerhard,
this is a known problem. Currently caching is not
very sophisticated, but we will start to implement
a really smart two level cache in near future. This
new cache implementation should solve most known problems.
Currently the user have to take care of a consistent
cache.
regards,
Armin
On Tue, 14 Oct 2003 15:23:36 +0200, <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I ran into a problem with implementing the collection attribute for a
1:n
> mapping:
>
> Since I didn't want to "polute" my persistent objects with any ODMG or
> even OJB specific imports, I just initialized my collection attributes
> (of
> type java.util.List) with ArrayLists when needed. This worked fine as
> long
> I was using a ObjectCachePerBrokerImpl cache, because when the
> transaction
> that created the object committed, the cache was cleared. So the next
> time
> the object was accessed, it was read fresh from the database and OJB set
> the collection attribute to a RemovalAwareCollection (or whatever the
> class descriptor specified).
>
> Now I'm trying to use a ObjectCacheDefaultImpl -- with the result that
> the
> new object is still cached when I access it again, and still has the
> ArrayList as List implementor of the collection attribute. The
> consequence
> is that removing entries from the List does not work, because OJB never
> gets notified of the removal.
>
> Who knows a way to initialize collection attributes with the proper OJB
> collection classes without making the object model dependent on OJB?
> Thanks for any hints!
>
> Gerhard
>
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