Hey Sergey, I'm convinced! I was just sending an e-mail to say so!
However my usecase requires me to replace the default JSON providor with a badgerfish one. So I'd like to discuss how to do 1 & 2. The spec says: "An implementation MUST support application-provided EntityProvider implementations and MUST use those in preference to its own pre-packaged EntityProvider implementations when either could handle the same request." I therefore think the best way to handle this is for the providerfactory to maintain two lists of providers - user defined and default. When deciding how to handle a request it first checks the user defined to see if any of these match. If no user defined providers match it the falls back to default list. I think this would handle both 1 & 2, implement the Spec correctly and would leave the spring syntax the same as I've discussed. Whatcha think? Barry On Feb 8, 2008 10:30 AM, Sergey Beryozkin <[EMAIL PROTECTED]> wrote: > Hi there > > Few more comments. > > Jersey allows for external providers be picked up from a classpath using a > ServiceProvider mechanism. > If we compare that approach with using the spring configuration to inject > entity providers, then we can see these are > just two different paths for external providers to get into the runtime. > In both cases there's really no need to specify all the entity providers > (message body readers/writers as per the new api) which may be needed for a > given application to function properly. > As I said earlier, JAX-RS requires for a bunch of types like Response, > JAXB-annotated ones, primitives, InputStream, Source, etc be supported out > of the box and after it gets finalized we'll have a TCK which will enforce > that a given implementation does provide it all out of the box. > Thus, a given user should only worry about external providers when none of > the shipped providers can go the job. In this case, requiring a user to > specify upfront a list of all the providers, including default ones (which > can be nested or indeed private classes not intended for the publication), > would be problematic IMHO. Among other things, it would limit the dynamism > of a given application which can have new types/formats introduced after it > has been started. I can also see users failing to specify the right list for > a given application for the first few times and getting frustrated. > > As far as adding external entity providers is concerned, I believe > there're primarily two cases : > 1. Runtime does not support the marshalling/unmarshalling of a given > custom type. In this case just specifying a custom provider's name would do > (as in the Barry's proposed patch) and the instance would be just added to > the list of existing providers, the runtime will take care of utilizing it, > based on its ProduceMime/ConsumeMime annotations and its support for a given > class type. > 2. Customer is not happy how, say, a given default provider works (that > is, how, say, it's converted into/from text/plain representations) and would > like to replace it with its own highly optimized implementation. JAX-RS > requires such custom providers be supported. IMHO, this is not the highest > priority issue for the CXF JAX-RS at this moment of time, but it's something > which need to be supported. How we do it I'm not sure yet, we could > introspect providers properly at the start. > > For example, lets say we have a default File provider (for all media types > */*), as mandated by the spec, this provider just uses older plain File > input/output streams wrapped into readers/writers. Customer wants to replace > it with a nio-based implementation. At the start-up we can check the > annotations for a given custom provider class and check if its instance > supports any of the types already supported by the runtime and if yes then, > for a given JAX-RS server endpoint, assume that a custom provider needs to > take charge... or perhaps just replace the default instance which will have > a global effect for al lthe endpoints. Something like that. > > Barry, have I convinced you :-) ? Would you be happy for your patch to > address an issue 1 above for a start but such that no replacement happens ? > > Thanks, Sergey > > > > > > Hi Barry > > Lets move a discussion on CXF-1425 to this list. > > In summary, > we're discussing with Barry whether a list of JAX-RS Entity Providers > (which know how to marshal/unmarshal given types) as > configured in a given spring xml, should override a default list or not. > > IMHO it should not be the case. It would put a strain on users. Users do > not need to know about the fact that a given Book class > will only be marshalled if a JAXB-aware provider is installed. If a given > set of returned types is large then it will get > complicated. User just need to know about the content type, XMLRootElement > and similar things. Users do not need to know about class > names for individual default providers, this will form some sort of a > contract between a runtime and a user thus making it more > difficult for us to change the things under the hood. > > For example, we can configure a Jetty handler, say we can add a Jetty > handler. When doing it we do not need to specify all other > types of handlers jetty may've set up under the hood. I believe we should > follow the same practise in this case. > > As far as duplicates is conncerned : this is easy, lets just have a Set of > full class names for individual providers. That would do > for a start. > > Thoughts ? > > Cheers, Sergey > > ---------------------------- > IONA Technologies PLC (registered in Ireland) > Registered Number: 171387 > Registered Address: The IONA Building, Shelbourne Road, Dublin 4, Ireland > > ---------------------------- > IONA Technologies PLC (registered in Ireland) > Registered Number: 171387 > Registered Address: The IONA Building, Shelbourne Road, Dublin 4, Ireland >
