[cdi-dev] @ThreadScoped?
Mark Struberg
struberg at yahoo.de
Sun Mar 20 16:04:56 EDT 2016
See Bean#getScope() and BeanManager#getContext()
Just uses Class and no Annotation instance.
Lgm
--------------------------------------------
On Sun, 20/3/16, Romain Manni-Bucau <rmannibucau at gmail.com> wrote:
Subject: Re: [cdi-dev] @ThreadScoped?
To: "Mark Struberg" <struberg at yahoo.de>
Cc: cdi-dev at lists.jboss.org, "Reza Rahman" <reza_rahman at lycos.com>
Date: Sunday, 20 March, 2016, 20:47
Le 20 mars 2016 20:40,
"Mark Struberg" <struberg at yahoo.de>
a écrit :
>
> A scope
annotation cannot have a flag.
>
Why? Technically it can
> LieGrue,
> strub
>
>
>
>
>
On Sunday, 20 March 2016, 20:25, Reza Rahman <reza_rahman at lycos.com>
wrote:
>
>
> >
> >
> >As discussed
elsewhere in this EG, even in the most pessimistic
reading
of the current spec, all that would
be needed is a flag on the existing
annotation. It's not out of the question at
all.
> >
> >On
Mar 20, 2016, at 1:36 PM, Manfred Riem <mnriem at gmail.com>
wrote:
> >
>
>
> >Why is changing @RequestScoped
out of the question?
> >>
> >>
> >>From
my perspective when an AsyncContext is started the request
is
still there.
>
>>
> >>
>
>>It is just being served by a different thread.
> >>
> >>
> >>Certainly there is a need to work
with the Servlet EG to figure out how
to
transfer “ownership” to the AsyncContext.
> >>
> >>
> >>Anyway my 2 cents
> >>
> >>
> >>Thanks!
>
>>
> >>
>
>>Kind regards,
> >>Manfred
Riem
> >>
>
>>
> >>On Mar 19, 2016, at
3:35 PM, Stephan Knitelius <stephan at knitelius.com>
wrote:
> >>>
> >>>I would certainly agree with
the assertion that in general it's not
advisable to execute a request with multiple
threads and that usually
single threaded
execution is sufficient.
>
>>>
> >>>However I
don't think ignoring it is an option. Concurrent
operations
can be launched even from CDI
beans. Yet we don't properly support context
propagation nor a context spanning all threads
launched from a request.
>
>>>
> >>>I know that
changing @requestScoped is probably out of the question,
but at least we should consider adding a new
context spanning all threads
and defining a
logical solution for context propagation that can be
explained to the end user.
>
>>>
> >>>
> >>>
>
>>>
> >>>On Fr., 11.
März 2016 at 17:17, Mark Struberg <struberg at yahoo.de>
wrote:
> >>>
> >>>Yes, but certain things in EE
are assumed to be handled on a single
thread. And if you run on a servr then this is
really not a blocker most
times. If I get
many paralllel requests hitting my box then I do not need
async handling _that_ often. The whole overhead
for setting up the new
thread, etc often
heavily exceeds the benefits.
>
>>>>So I would not put too much energy into
it…
> >>>>
> >>>>LieGrue,
> >>>>strub
>
>>>>
> >>>>>
Am 11.03.2016 um 15:44 schrieb Reza Rahman <reza_rahman at lycos.com>:
> >>>>>
>
>>>>> This is essentially in keeping with the
minimalist nature of the EE
concurrency JSR.
I believe most of it is left to vendors to do the right
thing for users. May be a good idea is this
language can be tightened up.
>
>>>>>
>
>>>>>> On Mar 11, 2016, at 6:01 AM, Mark
Struberg <struberg at yahoo.de>
wrote:
>
>>>>>> E
>
>>>>>> From the servlet spec:
> >>>>>>
> >>>>>> „Java
Enterprise Edition features such as Section 15.2.2,
“Web
Application Environment” on page
15-174 and Section 15.3.1, “Propagation of
Security Identity in EJBTM Calls” on page
15-176 are available only to
threads
executing the initial request or when the request is
dispatched to
the container via the
AsyncContext.dispatch method. Java Enterprise Edition
features may be available to other threads
operating directly on the
response object
via the AsyncContext.start(Runnable) method.“
> >>>>>>
> >>>>>> check
„available only to threads executing the initial
request“
> >>>>>>
> >>>>>> Also if you look
at the servlet AsyncContext then all the wording
is written as MAY and not as MUST.
> >>>>>>
> >>>>>> LieGrue,
> >>>>>> strub
> >>>>>>
> >>>>>>
> >>>>>>> Am 10.03.2016
um 19:52 schrieb Romain Manni-Bucau <
rmannibucau at gmail.com>:
> >>>>>>>
> >>>>>>> Hi Mark,
> >>>>>>>
> >>>>>>> think 2.3.3.4
states the opposite.
>
>>>>>>>
>
>>>>>>>
>
>>>>>>> Romain Manni-Bucau
> >>>>>>> @rmannibucau
| Blog | Github | LinkedIn | Tomitriber
> >>>>>>>
> >>>>>>> 2016-03-10
19:43 GMT+01:00 Mark Struberg <struberg at yahoo.de>:
> >>>>>>> Back from
JavaLand conference, so sorry for not kicking in
earlier.
>
>>>>>>>
>
>>>>>>> I not quite get the
argumentation chain. It’s that all triggered
by async servlet requests? And isn’t the
servlet spec also saying that all
the
request param etc may max be assigned to a single thread AT
A TIME!
> >>>>>>>
> >>>>>>> Means that it
might not be on multiple threads in parallel, but
the data is allowed to get moved from one
thread to another (disapearing
from the
first one), right?
>
>>>>>>> Would really need to dig into
the wording of the async servlets
spec
again, maybe has this in the back of his head?
> >>>>>>>
> >>>>>>> LieGrue,
> >>>>>>> strub
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>> Am
08.03.2016 um 14:43 schrieb Romain Manni-Bucau <
rmannibucau at gmail.com>:
> >>>>>>>>
> >>>>>>>> Hi
guys,
>
>>>>>>>>
>
>>>>>>>> following request scope
thread and to center the discussion on
the
thread safety part: do we work on this?
>
>>>>>>>>
>
>>>>>>>> Background: @RequestScoped
is often used as a ThreadLocal
instance
solution. A lot of SE or Batch implementations rely on it
from
what I saw as well as async
implementations reusing existing business logic
with this thread safety constraint.
> >>>>>>>>
> >>>>>>>> Proposal:
providing a @ThreadScoped implementation is cheap for
CDI and implemenation and would avoid the
headache we can have with
@RequestScoped.
Will also remove the quite dark side of the spec
regarding
servlet request and request scope
since now we would have a more natural
solution for all of these situation so
@RequestScoped goals wouldn't
collide as
much.
>
>>>>>>>>
>
>>>>>>>> Questions:
> >>>>>>>> - is it
automatically started as request scoped is (JMS, @Async,
...)? Alternative could be some configuration
in beans.xml (merged accross
the app):
> >>>>>>>>
> >>>>>>>>
<beans>
>
>>>>>>>> <scopes>
>
>>>>>>>> <thread>
> >>>>>>>>
<active>JMS</active>
> >>>>>>>>
<active>ASYNCHONOUS</active>
>
>>>>>>>> </thread>
> >>>>>>>>
</scopes>
>
>>>>>>>> </beans>
> >>>>>>>>
> >>>>>>>> -
start/stop API (this is typically an API the user should
be
able to control for its own threads)
> >>>>>>>> - CDI
2.*0*?
>
>>>>>>>>
>
>>>>>>>> wdyt?
>
>>>>>>>>
>
>>>>>>>> Romain Manni-Bucau
> >>>>>>>>
@rmannibucau | Blog | Github | LinkedIn | Tomitriber
> >>>>>>>>
_______________________________________________
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mailing list
>
>>>>>>>> cdi-dev at lists.jboss.org
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>>>>>>>
>
>>>>>>>
>
>>>>>>
>
>>>>>>
>
>>>>>>
_______________________________________________
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> >>>>>
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> >>>>
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>>>>_______________________________________________
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_______________________________________________
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> >>
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