All,
The Java EE 8 EG (which at least Antonio and myself, but also Antoine and
others representing CDI Spec Lead Red Hat are also EG members) has this
paragraph on CDI:
We plan to enhance the managed bean model to make ease of use features that
are currently available only to selected components available to all
managed beans via the mechanisms provided by CDI. In particular, we plan to
consider enhancements for declarative security by means of CDI interceptors
and for notifications for timed events by means of the CDI event and
observer mechanism.
I understand, it mostly aims at using CDI in other JSRs like 375 (somewhere
along the lines of Agorava or its precursor JSR 357;-)
If it's a completely new annotation (at least for CDI) would it be totally
wrong to define this by CDI itself?
Of course it's already in EJB (javax.ejb) and given Java EE 8 plans to
prune some of the EJB Spec, that is most clearly one to be touched in EE 8.
Unless it's something to be pruned of javax.ejb it won't go away from there
either. javax.enterprise.concurrent is so tiny and (unless using others
already;-) doesn't declare a single annotation of its own so far, so why
bother doing so for this one?
If it feels wrong in javax.ejb or should work entirely without EJB then
consider some place where CDI already has annotations (not just under its
main packages)
CDI 2 aims at a "Standard/Desktop" variant and another one like
"Full/Enterprise" depending on which of these benefit from such annotation
that may influence where to put it.
Werner Keil | JCP Executive Committee Member, JSR 363 Co Spec Lead |
Eclipse UOMo Lead, Babel Language Champion | Apache Committer | Advisory
Board Member, Java Track Chair, DWX '15
Twitter @wernerkeil | @UnitAPI | @JSR354 | @AgoravaProj | #EclipseUOMo
| #DeviceMap
| #DevOps
Skype werner.keil | Google+ gplus.to/wernerkeil
On Sat, Jan 17, 2015 at 4:58 PM, <cdi-dev-request(a)lists.jboss.org> wrote:
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Today's Topics:
1. Re: Building EJB-like @Asynchronous via interceptor in CDI
(Antonio Goncalves)
2. Re: Building EJB-like @Asynchronous via interceptor in CDI
(Mark Struberg)
------------------------------
Message: 2
Date: Sat, 17 Jan 2015 15:58:06 +0000 (UTC)
From: Mark Struberg <struberg(a)yahoo.de>
Subject: Re: [cdi-dev] Building EJB-like @Asynchronous via interceptor
in CDI
To: Antonio Goncalves <antonio.goncalves(a)gmail.com>
Cc: "cdi-dev(a)lists.jboss.org" <cdi-dev(a)lists.jboss.org>
Message-ID:
<
1807377505.2717120.1421510286847.JavaMail.yahoo(a)jws11147.mail.ir2.yahoo.com
>
Content-Type: text/plain; charset=UTF-8
@Antonio: and where/how to start this context? Boils down to the exactly
same issue.
Also remember that @RequestScoped IS already almost the same as it must be
there for every EJB invocation, @Asynchronous, @Startup @Singleton
@PostConstruct methods, JMS invocations, etc, etc
LieGrue,
strub
On Saturday, 17 January 2015, 16:31, Antonio Goncalves <
antonio.goncalves(a)gmail.com> wrote:
>
>
>@Arjan, remember the email I sent to the EE EG entitled "Status of the
Java EE 8 specifications". Bill Shannon replied :
>
>
>We agree on the long term vision. This is almost entirely a resource
issue. In order to do this, we have to stop doing something else, or we
have to delay the release. Based on the feedback we've gotten from the
community, the things we've chosen to work on right now are the most
important. We'd like to do what you suggest below as well, but it's most
likely going to have to be done later.
>
>
>
>So I don't know how we could "push" for an MR of the EE Concurrency
spec.
Any idea ? Except harassing Bill to add resources to the EE Concurrency
spec and taking other resources out somewhere else... I don't know how we
could do this.
>
>
>@Mark EE Concurreny could also add a @ThreadScoped like the one in Weld
(but with a EE meaning).
>
>
>Antonio
>
>
>
>
>On Sat, Jan 17, 2015 at 1:53 PM, Mark Struberg <struberg(a)yahoo.de> wrote:
>
>EE concurrency spec needs an update anyway. It currently doesn't
explicitly require @RequestScoped beans to be supported on a new Thread.
That breaks tons of frameworks and makes it barely usable in EE7.
>>
>>LieGrue,
>>strub
>>
>>
>>On Saturday, 17 January 2015, 13:12, arjan tijms <arjan.tijms(a)gmail.com>
wrote:
>>
>>
>>>
>>>
>>>Hi,
>>>
>>>
>>>
>>>On Sat, Jan 17, 2015 at 11:05 AM, Antonio Goncalves <
antonio.goncalves(a)gmail.com> wrote:
>>>
>>>@arjan Your example is base on ManagedExecutorService from the Java EE
Concurrency spec. That's one topic we've been wondering about : should the
@Asynchronous interceptor go to the Java EE Concurrency spec or not ? But
it looks like the spec might not be updated.
>>>
>>>
>>>The example I showed here would IMHO best be placed in the Java EE
Concurrency spec. That would in my opinion be a perfect analogy to
@Transactional and JTA. As given, the interceptor uses CDI/Interceptors and
Concurrency, so theoretically it could also be put into a third spec.
>>>
>>>
>>>Personally I would find it strange to put something in spec A, when it
may better belong in spec B, just because spec B is not updated. What's
holding the update of Java EE Concurrency back? If most of the EG members
would be of the opinion that an @Asynchronous interceptor belongs best in
Java EE Concurrency, then we can just update that spec, right?
>>>
>>>
>>>I know that MR releases can be quite fast and agile process wise, while
still packing some punch. JTA 1.2 itself was just such an MR, and JASPIC
1.1 was too. I was somewhat involved with JASPIC 1.1 (as community member)
and I think the setup time was pretty fast. Mid feb 2013 we created the
JIRA issues, the MR draft was published early march 2013 and the release
was with EE 7 end may 2013.
>>>
>>>
>>>If it would just be about putting a few interceptors formally in Java
EE Concurrency, then why not do such small update for it?
>>>
>>>
>>>Kind regards,
>>>Arjan
>>>
>>>
>>>>
>>>>Antonio
>>>>
>>>>
>>>>On Sat, Jan 17, 2015 at 12:32 AM, arjan tijms
<arjan.tijms(a)gmail.com>
wrote:
>>>>
>>>>Hi,
>>>>>
>>>>>
>>>>>
>>>>>On Fri, Jan 16, 2015 at 10:41 PM, Jozef Hartinger <
jharting(a)redhat.com> wrote:
>>>>>
>>>>>Hi Arjan,
>>>>>>
>>>>>>I did some changes recently in Weld interceptors and this
usecase
>> now works smoothly. The code is not part of a release yet. See this
>> test for a simple implementation of an @Async interceptor (basically
>> the same as your initial attempt). Note that the chain is repeatable
>> but at the same time it is not reset after dispatch to a different
>> thread so you no longer need the ThreadLocal nor any other
>> workaround.
>>>>>>
>>>>>
>>>>>
>>>>>That's quite a coincidence, it's indeed rather similar ;)
>>>>>
>>>>>
>>>>>I wonder how it now works though, as the InvocationContext
"ctx" does
not seem to be made aware that it's been dispatched to a different thread
from within the code. Does it use an internal thread local to keep state or
so?
>>>>>
>>>>>
>>>>>I'll also try to see what this does on OWB. Do you think this is
something that should work, or just something that Weld happens to support
regardless of the spec?
>>>>>
>>>>>
>>>>>Kind regards,
>>>>>Arjan
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>
https://github.com/weld/core/blob/master/tests-arquillian/src/test/java/o...
>>>>>>
>>>>>>Jozef
>>>>>>
>>>>>>
>>>>>>
>>>>>>On 01/16/2015 06:17 PM, arjan tijms wrote:
>>>>>>
>>>>>>Hi,
>>>>>>>
>>>>>>>
>>I'm attempting to emulate EJB's @Asynchronous in CDI using interceptors.
>>>>>>>
>>>>>>>Originally I had defined my interceptor as follows;
>>>>>>>
>>>>>>>@Interceptor
>>>>>>>@Asynchronous
>>>>>>>@Priority(APPLICATION)
>>>>>>>public class AsynchronousInterceptor implements Serializable
{
>>>>>>>
>>>>>>> private static final long serialVersionUID = 1L;
>>>>>>>
>>>>>>> @Resource
>>>>>>> private ManagedExecutorService managedExecutorService;
>>>>>>>
>>>>>>> @AroundInvoke
>>>>>>> public Object submitAsync(InvocationContext ctx) throws
>> Exception {
>>>>>>> return new
>> FutureDelegator(managedExecutorService.submit( ()-> {
>> return ctx.proceed(); } ));
>>>>>>> }
>>>>>>>
>>>>>>>}
>>>>>>>
>>>>>>>
>>>>>>>With FutureDelegator as follows:
>>>>>>>
>>>>>>>public class FutureDelegator implements Future<Object>
{
>>>>>>>
>>>>>>> private Future<?> future;
>>>>>>>
>>>>>>> public FutureDelegator(Future<?> future) {
>>>>>>> this.future = future;
>>>>>>> }
>>>>>>>
>>>>>>> @Override
>>>>>>> public Object get() throws InterruptedException,
>> ExecutionException {
>>>>>>> AsyncResult<?> asyncResult =
>> (AsyncResult<?>) future.get();
>>>>>>> if (asyncResult == null) {
>>>>>>> return null;
>>>>>>> }
>>>>>>>
>>>>>>> return asyncResult.get();
>>>>>>> }
>>>>>>>
>>>>>>> @Override
>>>>>>> public Object get(long timeout, TimeUnit unit) throws
>> InterruptedException, ExecutionException, TimeoutException
>> {
>>>>>>> AsyncResult<?> asyncResult =
>> (AsyncResult<?>) future.get(timeout, unit);
>>>>>>> if (asyncResult == null) {
>>>>>>> return null;
>>>>>>> }
>>>>>>>
>>>>>>> return asyncResult.get();
>>>>>>> }
>>>>>>>
>>>>>>> @Override
>>>>>>> public boolean cancel(boolean mayInterruptIfRunning) {
>>>>>>> return future.cancel(mayInterruptIfRunning);
>>>>>>> }
>>>>>>>
>>>>>>> @Override
>>>>>>> public boolean isCancelled() {
>>>>>>> return future.isCancelled();
>>>>>>> }
>>>>>>> @Override
>>>>>>> public boolean isDone() {
>>>>>>> return future.isDone();
>>>>>>> }
>>>>>>>
>>>>>>>}
>>>>>>>
>>>>>>>
>>>>>>>This of course didn't quite work, as the
InvocationContext will be
reset after the @AroundInvoke method returns, and an infinite intercept
loop results (on Weld).
>>>>>>>
>>>>>>>I got it to work though on Weld by using a thread local
check
>> to break that loop:
>>>>>>>
>>>>>>>@Interceptor
>>>>>>>@Asynchronous
>>>>>>>@Priority(PLATFORM_BEFORE)
>>>>>>>public class AsynchronousInterceptor implements Serializable
{
>>>>>>>
>>>>>>> private static final long serialVersionUID = 1L;
>>>>>>>
>>>>>>> @Resource
>>>>>>> private ManagedExecutorService managedExecutorService;
>>>>>>>
>>>>>>> private static final ThreadLocal<Boolean>
>> asyncInvocation = new ThreadLocal<Boolean>();
>>>>>>>
>>>>>>> @AroundInvoke
>>>>>>> public synchronized Object submitAsync(InvocationContext
>> ctx) throws Exception {
>>>>>>>
>>>>>>> if (TRUE.equals(asyncInvocation.get())) {
>>>>>>> return ctx.proceed();
>>>>>>> }
>>>>>>>
>>>>>>> return new
>> FutureDelegator(managedExecutorService.submit( ()-> {
>>>>>>> try {
>>>>>>> asyncInvocation.set(TRUE);
>>>>>>> return ctx.proceed();
>>>>>>> } finally {
>>>>>>> asyncInvocation.remove();
>>>>>>> }
>>>>>>> }));
>>>>>>> }
>>>>>>>
>>>>>>>}
>>>>>>>
>>>>>>>
>>>>>>>But I've got a feeling this works just by chance and not
because
the workaround is so clever.
>>>>>>>
>>>>>>>
>>>>>>>What do you guys think, what would be the best way to support
this
with the current CDI version? Or would CDI/Interceptors need something like
Servlet's async support, where the InvocationContext is put into async mode
whereafter it "simply" allows an other thread to continue processing on it?
>>>>>>>
>>>>>>>
>>>>>>>Kind regards,
>>>>>>>Arjan Tijms
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>_______________________________________________
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>>>>>>
>>>>>
>>>>>_______________________________________________
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>>>>>
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>>>>>
>>>>
>>>>
>>>>
>>>>--
>>>>
>>>>Antonio Goncalves
>>>>Software architect, Java Champion and Pluralsight author
>>>>
>>>>Web site | Twitter | LinkedIn | Pluralsight | Paris JUG | Devoxx France
>>>
>>>
>>>
>>>_______________________________________________
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>>>
>>>
>>
>
>
>
>--
>
>Antonio Goncalves
>Software architect, Java Champion and Pluralsight author
>
>Web site | Twitter | LinkedIn | Pluralsight | Paris JUG | Devoxx France
>
>
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