Carlo de Wolf wrote:
> The existing rule:
> EJB 3.2 EDR 4.3.13:
> "Therefore, a stateful or stateless session bean does not have to be
> coded as reentrant."
This is still correct. See below.
>
> vs
>
> 2011-10/message/8
> "For the stateful session beans and singleton session beans the
> returned reference will be for the same instance, and the bean must
> support reentrant calls to call a method on it."
May be I should remove that last part (", and ...") - see also below...
>
> EJB 3.2 EDR 4.10.13 does have an exception clause. Although it might
> be more correctly to state:
> "The container must ensure that only one thread can be executing a
> stateless or stateful session bean
> instance at any time.
> One implication of this rule is that an application cannot make
> loopback calls to a stateless or stateful
> session bean instance, unless the invocation were made on the result
> of SessionContext.get-
> BusinessObject (in conformance with the requirements of section 4.3.3).
> Barring an invocation though SessionContext.getBusinessObject,
> stateful and stateless session beans do not have to be coded as
> reentrant."
This is definitely needed to be fixed :(
My change (starting with "unless...") does seem to mix reentrance and
SessionContext.getBusinessObject, which is wrong (sorry). The
SessionContext.getBusinessObject result is intended to be used only for
the subsequent invocations (see 4.3.3), not reentrant calls (which are
not allowed on either SLSB or SFSBs).
I need to revert my change. I can also add a note stating that "The
object reference returned from SessionContext.getBusinessObject is to be
used for the subsequent invocations (see 4.3.3), not reentrant calls."
>
> To me it looks like we're mixing single-thread, multi-threaded and
> re-entrant wrongly.
Multi-threaded access of SFSB is allowed with locks and timeouts.
Reentrance is not.
Thanks for catching it,
-marina
>
> Carlo
>
> On 01/11/2012 09:44 PM, Marina Vatkina wrote:
>> 4.3.3 has this updated text (as suggested by Linda):
>>
>> •The getBusinessObject(Class businessInterface)method returns a
>> business object reference to the session bean’s business interface or
>> no-interface view. In the case of the no-interface view, the argument
>> is of the type of the bean class. Only session beans with an EJB 3.x
>> business interface or no-interface view are permitted to call this
>> method.
>> If a subsequent invocation were made on the result of
>> getBusinessObject, then:
>> •For a stateless session bean, the invocation would be delivered to
>> another stateless session bean instance.
>> •For a stateful session bean or singleton session bean, the
>> invocation would be delivered to the bean instance that returned the
>> reference. The existing rules regarding reentrancy would then apply.
>>
>>
>> What did I miss?
>>
>> thanks,
>> -marina
>>
>> Carlo de Wolf wrote:
>>> It looks like SessionContext.getBusinessObject on a SFSB still does
>>> not support single threaded re-entrant calls. Which it inherently is.
>>>
>>> http://java.net/projects/ejb-spec/lists/jsr345-experts/archive/2011-10/message/8
>>>
>>> EJB 3.2 EDR 4.3.3
>>> EJB 3.2 EDR 4.3.13
>>>
>>> Carlo
>>>
>>> On 12/17/2011 01:22 AM, Marina Vatkina wrote:
>>>> Experts,
>>>>
>>>> I uploaded EDR versions of both books of the EJB 3.2 spec. Please
>>>> review the changes before the books go to the JCP site for an
>>>> official submission. If you don't have any comments, please let me
>>>> know if you are ok with the EDR in its current state.
>>>>
>>>> The books have the change bars (the Optional Chapters changes are
>>>> very minor) and all the changes are listed in the Revision History
>>>> sections.
>>>>
>>>> Other than all the cleanups and clarifications (thank you very much
>>>> to everybody who helped with this activity), the following had been
>>>> added to/changed in the spec (the corresponding parts of the
>>>> revision history are prepended with *New:*) :
>>>>
>>>> * Added asynchronous session bean invocations and non-persistent
>>>> EJB Timer Service support to EJB 3.2 Lite.
>>>> * Removed restriction to obtain the current class loader; changed
>>>> ‘must not’ to ‘should exercises caution’ when using the Java I/O
>>>> package.
>>>> * Added support for the lifecycle callback interceptor methods of
>>>> stateful session beans to execute in a transaction context
>>>> determined by the bean’s transaction management type and any
>>>> applicable transaction attribute.
>>>>
>>>> Have a nice reading!
>>>>
>>>> -marina
>>>>
>>>>
>>>>
>>>
>