[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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 >
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 >>>>>>>
 >
 >>>>>>>
 >
 >>>>>>
 >
 >>>>>>
 >
 >>>>>>
 _______________________________________________
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