Hi Mike,
I agree, if I were up to implement that part in an app server, I also would
not pool EMs.
However given the fact, that I can't influence the behavior of the app
server, and if we find out, that the app server
does not restore the properties, then we propably need to introduce a
workaround-switch in our implementation
like "versant.resetPropertiesOnClear".
Regards,
Christian
On Fri, May 11, 2012 at 10:48 PM, michael keith <michael.keith_at_oracle.com>wrote:
> Hi Christian,
>
> Well, that's up to the container, but I suppose it would have to query the
> properties and save the initial values, then reset back to the default ones
> when reassigning. I wouldn't actually recommend doing it, since EM's are
> supposed to be lightweight.
>
> -Mike
>
>
> On 11/05/2012 9:35 AM, Christian Romberg wrote:
>
> Hi Mike,
>
> How should the app server reinitialize the entity manager instance then?
>
> Regards,
>
> Christian
>
> On Fri, May 11, 2012 at 3:22 PM, michael keith <michael.keith_at_oracle.com>wrote:
>
>> Hi Christian,
>>
>> The clear() method was not intended to reinitialize the EM, but is just a
>> method that causes all of the entities in the persistence context to be
>> detached. You can actually see an example on page 300 that highlights this
>> fact. The footnote you reference was just making reference to the fact that
>> a clear() call would need to be made on the EM in order for it to be
>> reused. It was not intended to be a complete description of how to reuse an
>> EM, or of other issues that might also need to be handled. I admit that it
>> could be a bit misleading, though...
>>
>> Regards,
>> -Mike
>>
>>
>> On 10/05/2012 9:58 AM, Christian Romberg wrote:
>>
>> Dear group,
>>
>> The spec (2.0) says, p.304, section 7.9.1, footnote 79:
>>
>> "The container may choose to pool EntityManagers: it instead of creating
>> and closing in each case, it may acquire one from its pool
>> and call clear() on it."
>>
>> What should happen with any property settings that were changed by the
>> user?
>> E.g. setFlushMode or any vendor-specific properties?
>>
>> Should clear() also reset them to the values configured for the
>> EntityManagerFactory?
>>
>> I think this would make sense to get a clean, reusable EntityManager.
>>
>> And if this is the common understanding of how clear() should work, I
>> suggest that we add
>> that in the spec.
>>
>> Thank you!
>>
>> Christian
>>
>> --
>> Christian Romberg
>> Chief Engineer | Versant GmbH
>> (T) +49 40 60990-0
>> (F) +49 40 60990-113 <%2B49%2040%2060990-113>
>> (E) cromberg_at_versant.com
>> www.versant.com<http://www.google.com/url?q=http%3A%2F%2Fwww.versant.com%2F&sa=D&sntz=1&usg=AFrqEzeeEBc_gN_8mxtt8xDB0tjXDXQVlw>|
>> www.db4o.com<http://www.google.com/url?q=http%3A%2F%2Fwww.db4o.com%2F&sa=D&sntz=1&usg=AFrqEzdo3Q40RwKQPBtnPIuBYQd1diFxJQ>
>>
>> --
>> Versant
>> GmbH is incorporated in Germany. Company registration number: HRB
>> 54723, Amtsgericht Hamburg. Registered Office: Halenreie 42, 22359
>> Hamburg, Germany. Geschäftsführer: Bernhard Wöbker, Volker John
>>
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>>
>>
>
>
> --
> Christian Romberg
> Chief Engineer | Versant GmbH
> (T) +49 40 60990-0
> (F) +49 40 60990-113
> (E) cromberg_at_versant.com
> www.versant.com<http://www.google.com/url?q=http%3A%2F%2Fwww.versant.com%2F&sa=D&sntz=1&usg=AFrqEzeeEBc_gN_8mxtt8xDB0tjXDXQVlw>|
> www.db4o.com<http://www.google.com/url?q=http%3A%2F%2Fwww.db4o.com%2F&sa=D&sntz=1&usg=AFrqEzdo3Q40RwKQPBtnPIuBYQd1diFxJQ>
>
> --
> Versant
> GmbH is incorporated in Germany. Company registration number: HRB
> 54723, Amtsgericht Hamburg. Registered Office: Halenreie 42, 22359
> Hamburg, Germany. Geschäftsführer: Bernhard Wöbker, Volker John
>
> CONFIDENTIALITY
> NOTICE: This e-mail message, including any attachments, is for the sole
> use of the intended recipient(s) and may contain confidential or
> proprietary information. Any unauthorized review, use, disclosure or
> distribution is prohibited. If you are not the intended recipient,
> immediately contact the sender by reply e-mail and destroy all copies of
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>
>
--
Christian Romberg
Chief Engineer | Versant GmbH
(T) +49 40 60990-0
(F) +49 40 60990-113
(E) cromberg_at_versant.com
www.versant.com<http://www.google.com/url?q=http%3A%2F%2Fwww.versant.com%2F&sa=D&sntz=1&usg=AFrqEzeeEBc_gN_8mxtt8xDB0tjXDXQVlw>|
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--
Versant
GmbH is incorporated in Germany. Company registration number: HRB
54723, Amtsgericht Hamburg. Registered Office: Halenreie 42, 22359
Hamburg, Germany. Geschäftsführer: Bernhard Wöbker, Volker John
CONFIDENTIALITY
NOTICE: This e-mail message, including any attachments, is for the sole
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