Hey,
Yes. The first one was almost what I had in mind.
I have a related question though (in the sense that pondering this
problem resulted in it).
Is the following allowed by the spec. I haven't read the complete
spec, so trying to find an answer was a bit difficult (being over 600
pages in total).
@Singleton
@Startup
public class MySingletonBean implements MySingletonBeanLocal
{
@EJB
private MySingletonBeanLocal self;
@PostConstruct
public void startup()
{
self.init();
}
public void init() {}
}
As you can see I inject the bean into itself (which should be fine,
being a singleton and all). But then I invoke a business method.
Currently this creates a deadlock in OpenEJB.
Like I mentioned I couldn't find an answer, but if the spec does in
fact not cover it, maybe it would be a good idea to do so, to ensure
consistent behavior among app servers.
Quintin Beukes
On Fri, Oct 16, 2009 at 4:20 AM, David Blevins <[email protected]> wrote:
> I'm not sure if I understand the overall goal.
>
> Is this a case where the code that intends to use the PeristenceContext
> (EntityManager) does not know the name of the persistence unit and therefore
> cannot look it up or have it injected?
>
> If so, it still should be possible to create a component that has an
> @PersistenceContext reference to the unit and then can pass it directly or
> indirectly to this more generic "work with any EntityManager" code. Perhaps
> with a Singleton pattern like this one http://bit.ly/vklEb
>
> You could also do a more generic version like this: http://bit.ly/10AsNt
>
>
> Hope that helps!
>
>
> -David
>
>
> On Oct 15, 2009, at 4:03 PM, Quintin Beukes wrote:
>
>> Basically I need a way to progammatically retrieve a unit manager.
>> Information regarding the PU is supplied to a module manager in an
>> core module which has no knowledge of the module until it's notified
>> of it.
>>
>> So, from your last e-mail, I assume it would then be possible to
>> annotate the persistence context in the Startup singleton of the
>> module, and then specify the class and field name to the module
>> manager, which would then use this information to construct a lookup
>> backwards, and then have it wrapped in a transaction (since the call
>> to the module manager is a business method invocation) - unless I
>> misunderstood the code.
>>
>> Though... 10 seconds ago I also thought of an option of doing a JNDI
>> lookup of the Singleton itself and then invoke on this reference -
>> this should wrap it in a transaction, which I can then use to pass in
>> an injected EntityManager reference?
>>
>> Quintin Beukes
>>
>>
>>
>> On Fri, Oct 16, 2009 at 12:29 AM, Quintin Beukes <[email protected]>
>> wrote:
>>>
>>> OK. So just to confirm that things are still the same.
>>>
>>> I know that unit names need not be unique, so I assume you still
>>> generate the unique ID suffix. How does OpenEJB then decide what to do
>>> with it. I tried looking around the code, but am a bit lost on where
>>> it injects these entity managers and how it decides which persistence
>>> unit to use. Could you perhaps tell me where to find this?
>>>
>>> Quintin Beukes
>>>
>>>
>>>
>>> On Thu, Oct 15, 2009 at 5:33 PM, Jean-Louis MONTEIRO
>>> <[email protected]> wrote:
>>>>
>>>> Hi Quintin,
>>>>
>>>> you can use JNDI to get a reference.
>>>> Have a look here
>>>>
>>>> http://www.nabble.com/Lookup-EntityManager-from-Stateless-EJB-Session-Bean-td24708299.html#a24737449
>>>>
>>>> http://www.nabble.com/Lookup-EntityManager-from-Stateless-EJB-Session-Bean-td24708299.html#a24737449
>>>>
>>>> Hope it helps.
>>>> Jean-Louis
>>>>
>>>>
>>>> Q Beukes wrote:
>>>>>
>>>>> Hey,
>>>>>
>>>>> When I have an EntityManager injected while having multiple
>>>>> persistence units, I do it by specifying the unit name, something
>>>>> like:
>>>>> @PersistenceContext(unitName="Some-PU")
>>>>> private EntityManager em;
>>>>>
>>>>> Is it possible to do this not by injection, but fetching it by name
>>>>> through an API of some sort?
>>>>>
>>>>> Quintin Beukes
>>>>>
>>>>>
>>>>
>>>> --
>>>> View this message in context:
>>>> http://www.nabble.com/Fetching-a-Persistence-Context-tp25910491p25910759.html
>>>> Sent from the OpenEJB User mailing list archive at Nabble.com.
>>>>
>>>>
>>>
>>
>
>
