[seam-dev] lobbying for alternative JPA provider support in 2.0.2.SP1

[Dan Allen]

Gavin,

I like that proposal. We give the method name semantic meaning (i.e.
setRenderFlushMode()). If a call really is made to
setManualFlushMode(), perhaps because of @Begin(flushMode = "MANUAL"),
then I can go along with an exception being thrown in that case.

I absolutely agree that we want to prevent flushing in the rendering
phase. I just wish it was supported as an extension by at least one
other JPA provider. I had hope for OpenJPA.

-Dan

On Tue, May 27, 2008 at 2:03 PM, Gavin King <gavin at hibernate.org> wrote:
> I think it is correct to call setManualFlushMode() before the render response
> phase. We should *never* flush changes to the database while in render
> response, and we should therefore avoid the cost of a dirty check.
>
> The correct fix would be to have two methods:
>
>  setManualFlushMode()
>  setRenderFlushMode()
>
> with diff implementations for non-Hibernate persistence providers:
>
>   setManualFlushMode() throws an exception
>   setRenderFlushMode() is a no-op
>
> for Hibernate, however, setRenderFlushMode()  would call setManualFlushMode().
>
> :-)
>
> On Tue, May 27, 2008 at 12:36 PM, Pete Muir <pete.muir at jboss.org> wrote:
>> It looks like we will end up having a 2.0.3 release. I would prefer not to
>> put this fix for which there is an easy workaround into this release
>> especially as I don't think this fix is correct (we shouldn't call
>> setManualFlushMode() from there at all).
>>
>> On 27 May 2008, at 16:37, Dan Allen wrote:
>>
>>> Seam devs,
>>>
>>> I am bringing a topic that happened in a private e-mail between Jay
>>> and I to the list.
>>>
>>> The main issue that I really want to see included in 2.0.2.SP1 is this
>>> fix for the PersistenceProvider (JBSEAM-3030). It bothers me that we
>>> are blatantly not supporting other JPA providers, even though we all
>>> know how important manual flushing is (trust that I find it the single
>>> most lacking feature in JPA). This is not a regression, but it sure
>>> feels like one.
>>>
>>> The backstory is that if you have at least one component with a
>>> persistence context (e.g. @In private EntityManager entityManager or
>>> @PersistenceContext private EntityManager entityManager), then Seam
>>> will attempt to put it into manual flush mode before rendering. When
>>> that happens, you are using the generic JPA provider, an exception is
>>> thrown, failing the rendering process. The only way around this issue
>>> is to implement your own PersistenceProvider and override the
>>> setManualFlushMode() to do nothing. My fix changes this exception to a
>>> log warning message.
>>>
>>> -Dan
>>>
>>> --
>>> Dan Allen
>>> Software consultant | Author of Seam in Action
>>>
>>> http://www.mojavelinux.com
>>> http://manning.com/dallen
>>>
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>>
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>
>
>
> --
> Gavin King
> gavin.king at gmail.com
> http://in.relation.to/Bloggers/Gavin
> http://hibernate.org
> http://seamframework.org
>



-- 
Dan Allen
Software consultant | Author of Seam in Action

http://www.mojavelinux.com
http://manning.com/dallen

NOTE: While I make a strong effort to keep up with my email on a daily
basis, life and work come first and, at times, keep me away from my mail
for a while. If you contact me, then don't hear back for more than a week,
it is very likely that I am excessively backlogged or the message was
caught in the spam filters. Please don't hesitate to resend a message if
you feel that it did not reach my attention.