[jax-rs-spec users] [jsr339-experts] Re: Re: Re: Re: Re: Re: Null response entity and writer providers

From: Sergey Beryozkin <>
Date: Tue, 26 Mar 2013 10:28:55 +0300

Sorry, will cut some of the text immediately below,

>>>>> IMO, if the JAX-RS method is returning a Response, then the JAX-RS
>>>>> method metadata is the default and any piece of it can be overriden by
>>>>> the user within the Response, including annotations. As an analogy, if
>>>>> the JAX-RS method has a @Produces, and the Response is set with a
>>>>> different media type, the overriden media type is honored.
>>>>> Also, +1 to no writers invoked if there is no response entity.
>>>> Sorry I may've moved the thread in some different direction, though
>>>> indeed, all agree that no writers are to be invoked in the case of a
>>>> null entity,
>>>> What confuses me even more now is that you seem to mean "override",
>>>> when referring to the annotations, while Marek thinks it is actually
>>>> 'add'.
>>>> We definitely need to have a common position on that :-)
>>> It MUST be add IMO. That's how it worked in JAX-RS 1.x RI.
>> ResponseBuilder did not have a method for adding the annotation in 1.1 ?
> No, it did not. Btw. if you looked at the ResponseBuilder javadoc and
> checked the "Since" information, you would not have to ask ;)
> java.lang.annotation.Annotation[])
> <,%20java.lang.annotation.Annotation%5B%5D)>
Yea, I know that. What confused me was you saying "add" was how it
worked for JAX-RS 1.1 RI, there were no alternatives there really, and
what we talk about now is about a new ResponseBuilder method.
>>> Also, I think it would be wrong to ask users to specify their method
>>> level annotations in the response builder, whenever they return a
>>> Response from a resource method. Annotation instances are not
>>> particularly easy to create...
>> Definitely not easy - why they users would *have* to do though ? It is
>> optional, if the user does not add them then method level annotations
>> are used.
>> May be we are talking about slightly different things ?
> I cannot recall the exact scenario, but I certainly have ran into a case
> where not adding the method level annotations broke some use case or
> even 1.x RI tests. My hunch is that it had something to do with not
> having the HttpMethod annotation available in a MBW or somewhere in the
> filter or interceptor. IMO the use case for rb.entity(Object,
> Annotation[]) is to e.g. provide support for additional annotations that
> vary based on entity content (validation, extra entity metadata for
> providers etc.) These typically do not interfere with static annotations
> placed on a resource method.
OK, Having ResponseBuilder optionally adding the annotations to the
statically declared ones makes sense, I just need to know the rules...
>>> Filters can then choose to add or override the response annotations
>>> as necessary.
>> How will the filter response context implementation know what the user
>> wants ? It is either add or override.
> I don't get your question. Filters either know what they do or should
> not touch the annotations at all. In general, I'd say that filters, too,
> will more often add new annotations or remove individual ones, if needed
> and will rarely replace all the annotations. But I do not know enough to
> be able to completely exclude such use case. Having the option in the
> API for low-level filters certainly does not hurt anyone.

The question is really simple.

Given on your earlier feedback I've got the impression that when
ContainerResponseContext#setEntity(Object entity, MediaType mt,
Annotation[] annotations) method is called, the provided 'annotations'
parameter effectively overrides what is already there.

You also say that the filters can remove some of the annotations. I
think what you mean is the following:

- ContainerResponseContext#setEntity(Object entity, MediaType mt,
Annotation[] annotations) does override the previous context value
- if the user wants to remove some of the annotations then
ContainerResponseContext#getEntityAnnotations would need to be used to
build a new Annotations array to be set on the context

Right ?


> Marek