On Feb 8, 2008 7:46 PM, Sergey Beryozkin <[EMAIL PROTECTED]> wrote: > Hi Jervis > > This seems to be a bit complicated. > I think that Barry's proposal is simple and effective. > > I doubt that we need to put some information or jars for all the default > providers be picked up from some directory. That would be similar to the > earlier proposal to provide them all in a spring configuration. Lets have > defaut providers created as usual, on startup (or dynamically later on, > based on a given consume/produce type) and be kept in one map. > > Lets have custom providers be picked up from either a spring configuration > (Barry's patch) or from the classpath using a usual jar's ServiceProvider > mechanism (same way as Jersey, this is something we can add later on) and > kept them in a second map. > > Second map is checked first, first map with defaults is checked > afterwards. It just works.
Agreed. Yes, this should work and it is simpler. > > About Aegis : it shoud have some sort of Aegis-specifoic annotations, > shouldn't it ? This annotation can server as a hint to an Aegis provider, > same was as @XMLRootElement serves as a hint to a JAXBProvider > Aegis binding does not need any annotations on its type class. > > Cheers, Sergey > > > > > > ----- Original Message ----- > From: "Jervis Liu" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Friday, February 08, 2008 11:34 AM > Subject: Re: JAX-RS custom provider spring config > > > > So based on what we have discussed so far, shall we agree on the > followings? > > > > > > > > 1. We do not need a programmatic API or Spring configuration to > configure > > Providers. Instead, we need to do three enhancements: > > > > a). Rather than hand-coded default (or pre-installed) providers that > need to > > initialized when CXF JAX-RS starts up, we need to enhance CXF so that > CXF > > can pick up all pre-installed providers from a dedicated directory. > > > > b). CXF JAX-RS should scan a dedicated directory so that if a new custom > > provider is installed or an old one is replaced in this directory, it > should > > be able to load the provider without rebooting the runtime. > > > > c). The algorithm that decides which provider to use may need some > updates > > as well. > > > > > > > > 2. We need the ability to specify an explicit provider to use (probably > > using annotations on the resource class or on the resource methods). > This > > feature is needed once we have more than one data binding providers, i.e > ., > > JAXBProvider and AegisProvider etc. > > > > > > > > Cheers, > > > > Jervis > > > > > > 2008/2/8 Liu, Jervis <[EMAIL PROTECTED]>: > > > >> There are a couple of issues that are covered or not covered yet by the > >> spec. As Barry mentioned, the use case 1&2 are actually already covered > by > >> the spec. I.e, the JAX-RS runtime should maintain a list of default or > >> pre-installed providers, for any custom providers installed by the > users, > >> they should be ordered before pre-installed providers. Please refer to > the > >> spec on the algorithm of how a provider is selected. > >> > >> One case which is not covered by the spec I believe, is the ability to > >> explicitly specify a provider to use on the resource class or resource > >> method. For example, lets say we have two data binding Providers, one > is > >> JAXBProvider, one is AegisProvider. In some cases, I may need to say > >> explicitly that I want to use Aegis binding to marshal/unmarshal all my > data > >> types other than letting the jax-rs runtime to find the most > appropriate > >> provider for me. > >> > >> Cheers, > >> Jervis > >> > >> > -----Original Message----- > >> > From: Barry Fitzgerald [mailto:[EMAIL PROTECTED] > >> > Sent: 2008年2月8日 18:50 > >> > To: [email protected] > >> > Subject: Re: JAX-RS custom provider spring config > >> > > >> > Hey Sergey, > >> > > >> > 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 > >> > > > >> > >> ---------------------------- > >> 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 >
