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From Lars-Fredrik Smedberg <itsme...@gmail.com>
Subject Re: Question on EJB and concurrency
Date Mon, 01 Sep 2014 10:15:02 GMT
@Romain

Thanks for the answers... in question 4 I meant that if I annotate a bean
with @TransactionAttribute will it still work as expected regardless of if
the bean instance is accessed with multiple threads at the same time or
not  (in the case of singleton read lock or singleton bean concurrency
management )?
On 1 Sep 2014 11:42, "Romain Manni-Bucau" <rmannibucau@gmail.com> wrote:

> Hi
>
> 1. true
> 2. @ConcurrencyManagement(BEAN -> lock free, @Lock(READ)
> reentrantLock.readLock().lock/unlock is called (performance wise
> difference is not that important in general)
> 3. it should. comparison is fair
> 4. @TransactionAttribute defines the transactional context you want,
> required will create or inherit running tx, required_new will always
> creates a new one. CDI beans are "support" (ie I don't care)
>
>
>
> Romain Manni-Bucau
> Twitter: @rmannibucau
> Blog: http://rmannibucau.wordpress.com/
> LinkedIn: http://fr.linkedin.com/in/rmannibucau
> Github: https://github.com/rmannibucau
>
>
> 2014-09-01 10:32 GMT+02:00 Lars-Fredrik Smedberg <itsmeden@gmail.com>:
> > Hi
> >
> > I have some questions on EJBs and concurrency, I hope someone can shed
> some
> > light on the following questions:
> >
> > 1. I have understood that the annotations @ConcurrencyManagement and
> @Lock
> > only are applicable to Singelton EJBs and that the default values are
> > container managed concurrency and WRITE lock, correct?
> > 2. What is the difference between annotating with
> > @ConcurrencyManagement(BEAN) vs using container managed concurrency and
> > annotating @Lock(READ) ? Is there better performance wise to use BEAN
> > managed concurrency if thread safety is no issue?
> > 3. Will an EJB annotate @ConcurrencyManagement(BEAN) simply ignore any
> > @Lock annotations? Is this the EJB equivalent to an @ApplicationScoped
> CDI
> > bean when it comes to concurrency?
> > 4. Is this a totally separate function from using tx and annotation
> > @TransactionAttribute ? I mean in the case of concurrent access to
> business
> > method in a bean that e.g. has @TransactionAttribute(REQUIRED) I will
> start
> > multiple transactions?
> >
> > Thanks
> >
> > Regards
> > Lars-Fredrik
> >
> > --
> > Med vänlig hälsning / Best regards
> >
> > Lars-Fredrik Smedberg
> >
> > STATEMENT OF CONFIDENTIALITY:
> > The information contained in this electronic message and any
> > attachments to this message are intended for the exclusive use of the
> > address(es) and may contain confidential or privileged information. If
> > you are not the intended recipient, please notify Lars-Fredrik Smedberg
> > immediately at itsmeden@gmail.com, and destroy all copies of this
> > message and any attachments.
>

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