[hibernate-dev] 6.0 - Session#createFilter

[Christian Beikov]

As far as I understand from the 
documentation(https://docs.jboss.org/hibernate/orm/3.3/reference/en/html/objectstate.html#objectstate-filtering), 
it can be used to filter collections and arrays. I don't know if it only 
works for persistent collections but since arrays are also mentioned, I 
guess not.
I'd expect the collection or array to be filtered and projected 
in-memory if possible, thus not executing a query unless needed for a 
lazy collection or additional from clause.

If that understanding is wrong, please help me understand what the 
purpose is then.

Am 02.01.2017 um 12:37 schrieb Steve Ebersole:
> I think you are not understanding createFilter:
>
> http://docs.jboss.org/hibernate/orm/current/javadocs/org/hibernate/Session.html#createFilter
>
> Again, to call filter you'd have to have access to the Collection you 
> want to filter.
>
> On Mon, Jan 2, 2017 at 2:40 AM Christian Beikov 
> <christian.beikov at gmail.com <mailto:christian.beikov at gmail.com>> wrote:
>
>     Let's say we have this entity with an attribute that is not
>     directly exposed.
>
>     class EntityA { String field; }
>
>     and then you pass a collection of EntityA instances to
>     createFilter like
>
>     Collection<EntityA> collection = ...
>     collection = session.createFilter(collection, "field =
>     'abc%'").getResultList();
>
>     See my point? Since Hibernate can access the field directly, this
>     works, but with streams you'd need to expose the field via a
>     getter so you can filter for it.
>
>
>     Am 02.01.2017 um 09:25 schrieb Steve Ebersole:
>>
>>     Could you explain the situation where you would map a collection
>>     but not expose it?  And btw even create createFilter would not
>>     work there because you have to pass createFilter the collection
>>
>>
>>     On Mon, Jan 2, 2017, 2:15 AM Christian Beikov
>>     <christian.beikov at gmail.com <mailto:christian.beikov at gmail.com>>
>>     wrote:
>>
>>         Well it does when you consider that there might be no getter
>>         for a field. With createFilter you could still filter the
>>         result list without exposing direct access to the field via a
>>         getter.
>>
>>         Am 02.01.2017 um 08:52 schrieb Steve Ebersole:
>>>         Field-access would have zero bearing on this
>>>
>>>         On Mon, Jan 2, 2017 at 1:30 AM Christian Beikov
>>>         <christian.beikov at gmail.com
>>>         <mailto:christian.beikov at gmail.com>> wrote:
>>>
>>>             Sounds good to me, but maybe we could do a poll to see
>>>             if people are
>>>             using this? I don't know if the filter also works for
>>>             field based access
>>>             strategy, but that could be a reason for keeping it around.
>>>
>>>             Regards,
>>>
>>>             Christian
>>>
>>>
>>>             Am 31.12.2016 um 21:00 schrieb Steve Ebersole:
>>>             > As I have not been hearing hardly any feedback on
>>>             these 6.0 design
>>>             > questions I have been trying to start, I'll be doing
>>>             something different in
>>>             > this and any additional emails.. I'll state what I
>>>             propose to do and if
>>>             > anyone has issue with it they can make a counter
>>>             proposal.  Otherwise I
>>>             > plan on following through with my proposal.
>>>             >
>>>             > I plan on removing Session#createFilter. There are
>>>             numerous reasons why
>>>             > which I can discuss if anyone is interested in
>>>             exploring this.
>>>             >
>>>             > Ultimately I think it makes sense to handle this via
>>>             Java 8 streams[1]
>>>             > although I am not sure that needs to happen in 6.0
>>>             >
>>>             > [1] https://hibernate.atlassian.net/browse/HHH-10962
>>>             > _______________________________________________
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>>>
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>>
>