On Oct 24, 2011, at 4:53 PM, Sergey Beryozkin wrote:
>> The person that made the suggestion has a lot of experience writing tools. Maybe I'm repeating myself, but his point was simply that using Response<T> simply provides more static information that a tool can use to build a service description of some kind (in HTML or WADL or similar).
>>
> Well, that is quite important, but I don't see what a tool can do with Response<List<Bean>> or Response<Set<X>>.
If the return type is Response, clearly the tool can't say much about the entity type. If the return type is something like Response<List<Bean>>, a tool can at least apply the algorithm defined in Chapter 8 of the JAXB 2.2 specification (Java Type To XML).
>
>> This also holds for the case in which T is _not_ a generic type. I.e., even if the method returns Response<Bean>. Services supporting hypermedia would return Response<Bean> instead of Bean if using link headers.
>>
> Response<Bean> is more interesting. I don't know - there has to be some kind of compromise there.
>
> The question is, who is the receiver of Response<T>. It does not give a user writing a server code anything, it does not.
>
> So. All the users writing Response in their signature will need to deal with the rigidness of generics. Some users have the code returning Bean, others SuperBean, they ll have to start typing those generics in - even though it does not help them in creating a RESTful service. They will lose the 'protection' of non-generic Response.
I suspect the case in which the same method returns entities whose representations come from different Java types isn't the norm. For those cases, they can use Response<?>.
>
> What the tool can do with '? extends Bar' ?.
Again, I don't think this is the norm. But of course this wouldn't help the tool as much.
>
> As far as the tooling is concerned. In CXF we addressed this issue by adding a dedicated annotation. For example, facilitating the auto-generation of WADL and helping users produce a robust server side code are two orthogonal issues.
How does that annotation look like? For the case in which wildcards are needed in Java types, I'd expect that annotation to be quite hairy. Is it not?
-- Santiago
>
> Now we also have TypeLiteral on the client side.
>
> Thus, again, the questions are:
>
> - who is the ultimate 'receiver' of this extension ?
> - what happens on the client side when this extension is added
> - Is it all to make the auto-generation of WADL simpler ? If yes - can we think of other approaches ?
>
> Thanks Sergey
>
>
>> -- Santiago
>>
>>>>> On 19/10/11 14:34, Santiago Pericas-Geertsen wrote:
>>>>>>
>>>>>> On Oct 19, 2011, at 7:41 AM, Sergey Beryozkin wrote:
>>>>>>
>>>>>>> Thanks, so I'm wondering why would we want to make an effort and let users write
>>>>>>>
>>>>>>> 'public Response<List<Bean>>'
>>>>>>
>>>>>> I think it's mostly for readability and tooling. Any form of static tooling would benefit from the extra type information; and it's arguably more readable for developers as well.
>>>>>>
>>>>>> We sort of went in this direction with WriteToHandlerContext<T> and ReadFromHandlerContext<T>.
>>>>>>
>>>>>> -- Santiago
>>>>>>
>>>>>> PS: I think the first example in JAX_RS_SPEC-108 has a typo, and should return Response.
>>>>>>
>>>>>>> What is a List<Bean> on the wire ? It can not be properly described.
>>>>>>> That of course can work, we can even customize easily the wrapper name, etc, but I'm not sure it's a spec level issue at all
>>>>>>>
>>>>>>> Cheers, Sergey
>>>>>>>
>>>>>>> On 19/10/11 12:29, Marek Potociar wrote:
>>>>>>>> See here for more explanation: http://java.net/jira/browse/JAX_RS_SPEC-108
>>>>>>>>
>>>>>>>> Marek
>>>>>>>>
>>>>>>>> On 10/16/2011 06:09 PM, Sergey Beryozkin wrote:
>>>>>>>>> Hi
>>>>>>>>>
>>>>>>>>> On 14/10/11 17:20, Marek Potociar wrote:
>>>>>>>>>> Hello experts,
>>>>>>>>>>
>>>>>>>>>> we've privately received some suggestions to make Req/Resp + builders generic.
>>>>>>>>>>
>>>>>>>>>> + The advantage would be the type safety as well as potential to preserve type information so that GenericEntity does
>>>>>>>>>> not have to be utilized directly (e.g. HTTP resource methods that produce Response currently would be able to better
>>>>>>>>>> declare the actual response entity type, provided the entity types produced share a common ancestor).
>>>>>>>>>>
>>>>>>>>>> - The main disadvantage I can think of is that generic req/response processing would (if correctly typed) require the
>>>>>>>>>> extra "<?>" in many scenarios.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> What advantage can that give to the client code, would that interfere with the use of TypeLiteral in Response.getEntity
>>>>>>>>> ? Personally I can live with the use of GenericEntity on the server side because IMHO the use of explicit collections is
>>>>>>>>> not in 'mainstream', it seems most users are happy with dealing with plain beans - those can be better validated,
>>>>>>>>> extended and described
>>>>>>>>>
>>>>>>>>> Cheers, Sergey
>>>>>>>>>
>>>>>>>>>> Thoughts?
>>>>>>>>>>
>>>>>>>>>> Marek
>>>>>>>
>>>>>>>