Resent as requested by Martina.
Begin forwarded message:
> From: Adam Bien <abien_at_adam-bien.com>
> Subject: Re: [jsr345-experts] XXX Transactional execution of a PostConstuct or PreDestroy method of a singleton session bean
> Date: 12. September 2011 13:38:40 MESZ
> To: marina.vatkina_at_oracle.com
>
> Hi Marina,
>
> if you are accessing a EntityManager you will need to start a transaction. Usually you also would like to access the DB in a TX to have consistent reads and rely on defined isolation level settings.
> @PreDestroy is even more crucial. It could be used to flush the cache to a DB.
>
> I use sometimes Singletons in single node clusters for deferred writes.
>
> thanks!,
>
> adam
>
>
>
> On 10.09.2011, at 02:45, Marina Vatkina wrote:
>
>> Adam,
>>
>> Can you describe the issue in more details? When will pre-fetching data in Singleton's PostConstuct would need to be transactional?
>>
>> thanks,
>> -marina
>>
>> Adam Bien wrote:
>>> +1 for transactional callbacks. Had the issue in @Singletons, which prefetched the data from DB already.
>>> On 07.09.2011, at 14:40, Pete Muir wrote:
>>>
>>>
>>>> In general, it's very useful for a postconstruct/predestroy method to be able to be called within a transaction.
>>>>
>>>> For example, consider seeding data into a database (singleton with @Startup and an @PreDestroy), logging user access (http session scoped SFSB) and so on.
>>>>
>>>> On 7 Sep 2011, at 03:18, Marina Vatkina wrote:
>>>>
>>>>
>>>>> Experts,
>>>>>
>>>>> Let's clarify transactional support for PostConstuct or PreDestroy methods.
>>>>>
>>>>> a) PostConstuct or PreDestroy methods of a singleton session bean can be executed in a transaction, while other bean types do not seem to allow this. Why would the singleton bean is different from any other bean?
>>>>>
>>>>> b) Why would the transactional attribute be specified differently for a singleton vs. other beans? See e.g. an XXX marker under section "8.3.7 Specification of the Transaction Attributes for a Bean’s Methods" in one of the bullets of the "Transaction attributes are specified for the following methods:" text:
>>>>>
>>>>> <...>
>>>>>
>>>>> For a singleton session bean, the transaction attributes are specified for the PostConstruct and PreDestroy lifecycle callback interceptor methods, if any. In order to specify the transaction attribute for a PostConstuct or PreDestroy method of a singleton session bean, the transaction attribute must be specified for the method(s) on the bean class, rather than for a superclass or PostConstruct or PreDestroy interceptor method."
>>>>>
>>>>> thanks,
>>>>> -marina
>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>>
>
>