[cdi-dev] Building EJB-like @Asynchronous via interceptor in CDI
Romain Manni-Bucau
rmannibucau at gmail.com
Sat Jan 17 08:03:35 EST 2015
+1 for ee concurrency
Le 17 janv. 2015 13:53, "Mark Struberg" <struberg at yahoo.de> a écrit :
> 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 at gmail.com>
> wrote:
>
>
> >
> >
> >Hi,
> >
> >
> >
> >On Sat, Jan 17, 2015 at 11:05 AM, Antonio Goncalves <
> antonio.goncalves at 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 at gmail.com>
> wrote:
> >>
> >>Hi,
> >>>
> >>>
> >>>
> >>>On Fri, Jan 16, 2015 at 10:41 PM, Jozef Hartinger <jharting at 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/org/jboss/weld/tests/interceptors/thread/async/AsyncInterceptor.java
> >>>>
> >>>>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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> >>>https://lists.jboss.org/mailman/listinfo/cdi-dev
> >>>
> >>>Note that for all code provided on this list, the provider licenses the
> code under the Apache License, Version 2 (
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> provided on this list, the provider waives all patent and other
> intellectual property rights inherent in such information.
> >>>
> >>
> >>
> >>
> >>--
> >>
> >>Antonio Goncalves
> >>Software architect, Java Champion and Pluralsight author
> >>
> >>Web site | Twitter | LinkedIn | Pluralsight | Paris JUG | Devoxx France
> >
> >
> >
> >_______________________________________________
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> >
> >
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