stateful appscoped = @singleton @lock(write)

Romain Manni-Bucau
Twitter: @rmannibucau
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2014-09-01 16:27 GMT+02:00 Lars-Fredrik Smedberg <[email protected]>:
> Hi Romain
>
> A follow up question. What will the difference between a @Singleton EJB and
> a @Statefull @ApplicationScoped EJB be? Is it only the fact that the latter
> will have a CDI-proxy in fron of the EJB-proxy but function wise they will
> work the same?
>
> Regards
> Lars-Fredrik
>
>
> On Tue, Aug 26, 2014 at 4:50 PM, Romain Manni-Bucau <[email protected]>
> wrote:
>
>> Hi
>>
>> 2014-08-26 16:45 GMT+02:00 Lars-Fredrik Smedberg <[email protected]>:
>> > Hi
>> >
>> > I have a few questions on EJB, CDI and Concurrency when I read
>> > http://tomee.apache.org/examples-trunk/access-timeout/README.html, I
>> read
>> >
>> > - Concurrent access to a @Stateful bean is serialized by the container.
>> >
>> > I also understand that I can annotate the EJBs with any of the CDI-scopes
>> > (in my case I'm interested in @RequestScoped, @SessionScoped and
>> > @ApplicationScoped).
>> >
>> > Questions:
>> >
>> > 1. If I annotate the @Stateful bean with @RequestScoped I assume that I
>> get
>> > a separate bean instance for each call? Correct?
>>
>> yes
>>
>> > 2. If I annotate the @Stateful bean with @SessionScoped I assume that I
>> per
>> > sesion get a separate bean instance that allows concurrent calls withing
>> > that particular session without wait? Correct?
>>
>> you get one instance by session and calls are serialized if needed to
>> ensure thread safety
>>
>> > 3. If I annotate the @Stateful bean with @ApplicationScoped I assume
>> that I
>> > per application get one bean instance that allows concurrent calls
>> without
>> > wait? Correct?
>> >
>>
>> same as before, thread safety is ensured
>>
>> > The reason I ask is that as far as I understand CDI does not have any
>> > concurrency management but the EJB has. What will be the case when doing
>> as
>> > above?
>> >
>> > Please help me get some in-depth understanding on this.
>> >
>>
>> for @AppScoped => look @javax.ejb.Singleton and @Lock which is surely
>> better
>>
>> > Thanks
>> > Lars-Fredrik Smedberg
>> >
>> >
>> >
>> > --
>> > 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 [email protected], and destroy all copies of this
>> > message and any attachments.
>>
>
>
>
> --
> 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 [email protected], and destroy all copies of this
> message and any attachments.

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