[hibernate-dev] 6.0 - Session#createFilter

[Steve Ebersole]

The alternative atm is to directly query against the owning entity or
directly against the element.  Granted that last one assumes that the
element defines a mapped reference back to the owner to be able to apply
the restriction based on the FK, but that's the more normal mapping anyway.

So e.g., if you have a filter like: `session.createFilter(
customer.getOrders(), "orderDate < currentDate() - {3 months}" )`, instead
you'd do: `select elements( c.orders ) from Customer c join c.orders where
c.id = :customerId and o.orderDate < currentDate() - {3 months}` or `select
o from Order o where o.customer = :customerId and o.orderDate <
currentDate() - {3 months}`.

Ultimately I'd also like to see "stream queries".  This would take 2 forms:

   1. Session#stream( Order.class )...
   2. customer.getOrders().stream()... (this works because
   customer.getOrders() is a PersistentCollection and we'd control the
   stream() impl)


The reasons for removing it are:

   1. It dirties the HQL grammar.  A valid filter string is literally""
   (empty String) which means that the grammar needs to allow for that.
   2. IMO it is a clunky API
   3. I am pretty sure noone uses it.  Not to pick on Christian, but he is
   a pretty advanced user and even he did not understand its use which speaks
   both to its obscurity as well as its clunkiness.


On Mon, Jan 2, 2017 at 7:08 AM Gunnar Morling <gunnar at hibernate.org> wrote:

> > I plan on removing Session#createFilter.  There are numerous reasons why
> which I can discuss if anyone is interested in exploring this.
>
> I'm curious, what are the reasons for removing it? And if we remove it,
> what's the alternative for people to use?
>
>
> 2016-12-31 21:00 GMT+01:00 Steve Ebersole <steve at hibernate.org>:
>
> 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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