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[javaee-spec users] [jsr342-experts] JAX-RS (Servlet), EJB and CDI alignment

From: Antonio Goncalves <antonio.goncalves_at_gmail.com>
Date: Sun, 24 Jun 2012 13:02:59 +0200

Hi all,

I was reading through JAX-RS 2.0 edr3 specification and had some questions
about the alignment with other specs. First of all I can see that @Context
is still used to inject UriInfo, HttpHeaders of even servlet resources.
When I read the spec (3.2) I see the word *Resource* in the
definition : "*_at_Context
Injects an instance of a supported resource*". So why not use the @Resource
annotation ? In the case of JAX-RS @Inject looks more appropriate
(@Resource deals with JNDI names and so on).

For asynchrony (8) they need to inject an ExecutionContext. Again, this is
done with @Context, which is a real shame as ExecutionContext sounds like
SessionContext (which is injected with a @Resource or @Inject). Asynchrony
in JAX-RS is done with the @Suspend annotation, it has a timeout and a time
unit attributes (@Suspend(timeOut = 15, timeUnit = TimeUnit.SECONDS)) while
we have @Asynchronous in EJB (without any attributes). In the spec there is
even a sample mixing both :

@Stateless
@Path("/")
class EJBResource {

  @GET *_at_Suspend @Asynchronous*
  public void longRunningOp(@Context ExecutionContext ctx) {
    executeLongRunningOp();
    ctx.resume("Hello async world!");
  }
}

Servlet also has it's own mechanism to deal with asynchronous requests. In
the EJB group we talked about "standardizing" @Asynchronous and giving it
to other specifications. Couldn't it be the case with JAX-RS (and Servlet,
but I think this topic has heavily been debated during Servlet 3.0) ?

And in a more general question, do we really need to push alignment between
specs when it's possible ?


-- 
Antonio Goncalves
Software architect and Java Champion
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