users@javaee-spec.java.net

[javaee-spec users] [jsr342-experts] Re: custom injection annotations

From: Antonio Goncalves <antonio.goncalves_at_gmail.com>
Date: Tue, 6 Nov 2012 09:53:43 +0100

Hi all,

I am the opposite of Markus on this one. I don't what to ask myself too
many questions : need to inject a persistence context ? @Inject
PersistenceContext. Need to inject an EJB ? @Inject MyEJB... and so on. I'm
already disappointed to see @Context in JAX-RS. The programming model
should be as easy as possible.

Then comes the "I don't want to depend on CDI". This to me sounds a bit
strange. CDI 1.1 is standardizing bootstrapping in Java SE, so what's the
issue ? If the Batch JSR needs CDI outside EE it just bootstraps CDI in
Java SE. Then, depending on CDI only really means depending on another
external jar (piece of cake for Maven)

I would like to see less custom technical annotations (let's use @Inject
when we can) and in favour of more business annotation that developers can
create (thanks to Stereotypes and Qualifiers)

Antonio


On Tue, Nov 6, 2012 at 6:48 AM, Markus Eisele <myfear_at_web.de> wrote:

> Hi Bill/All,
>
> Still very much split myself. I'm in favor of CDI. I simply don't like to
> see @Inject all over the place.
> We already have a ton of custom annotations (e.g. @EJB) and if we treat
> them as a legacy artifact only we will probably end up with a programming
> model that needs good naming conventions (again) to be helpful.
>
> @Inject
> private MyBoundary boundaryEJB;
>
> @Inject
> private JobContext batchContext;
>
> This moves the problem to the user but should be solved in the platform.
> Having custom injection annotations makes this more readable and easier to
> follow in the code (at least for me).
>
> I would like to see the expansion of use of CDI stereotypes (aka
> meta-annotations / stacked stereotypes) and require every EE spec to
> provide a CDI based injection annotation.
> They should be free to provide additional ways for supporting standalone
> environments (e.g. via additional @Qualifiers).
>
> - M
>
>
> On 6 November 2012 01:10, Bill Shannon <bill.shannon_at_oracle.com> wrote:
>
>> I'd like to follow up on an issue we raised at the Java EE 7 BOF
>> about the use of custom injection annotations.
>>
>> For example, should the Batch spec define
>>
>> @BatchContext
>> private JobContext ctx;
>>
>> or should it use
>>
>> @Inject
>> private JobContext ctx;
>>
>> The former is effectively a custom injection annotation unrelated to CDI.
>>
>> The latter introduces a dependency on CDI.
>>
>>
>> In your opinion, which is preferred? It seemed that the EE 7 BOF
>> audience was
>> pretty evenly split on this one, and I can see arguments for either
>> position.
>>
>> If @Inject is preferred, should we allow custom annotations at the
>> discretion
>> of the spec author, or should we disallow custom annotations entirely?
>>
>> If custom injection annotations are allowed, should CDI make it easy to
>> define them, e.g., using something like:
>>
>> @Stereotype
>> @Inject
>> public @interface BatchContext { }
>>
>> If CDI supported this easily, applications could even define their own
>> injection annotations.
>>
>> Should custom injection annotations be a legacy artifact that we need
>> to continue to support, or should we recognize it as a part of the
>> Java EE programming model and use it widely?
>>
>
>


-- 
Antonio Goncalves
Software architect and Java Champion
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