On 8 Oct 2010, at 16:49 , Ivo Ladage-van Doorn wrote: > Evaluating the code of the REST services, Angelo and I identified two issues > with the current implementation: > - The current implementation of the Apache Wink application bundle > embeds the JAX-RS packages and exports them. REST services using JAX-RS > should add JAX-RS annotations which packages are provided by the Wink > application bundle. This causes an unwanted dependency between the Wink > bundle and the REST service bundle.
So create a separate bundle that just exports the JAX-RS package and have Apache Wink import that one. > - In the current implementation a ServiceTracker is used to listen > to the availability of _any_ service, checking if its class contains the > @Path annotation. This service must implement _an_ interface (no matter which > one) in order for this to work properly. Especially the fact that the service > should implement _any_ interface is error-prone and should be improved. That's not entirely true. A service does not need to implement an interface at all to be registered in the service registry. You can register it with an implementation class, or even just "java.lang.Object". Not very pretty either though. > There are two possible solutions: > - Introduce a new bundle with some RESTService interface, > implemented by REST services and picked up whiteboard style by the Wink > application bundle to register them in the Wink framework. Also the JAX-RS > classes should be moved to this bundle. I like the whiteboard pattern here. I do not like the "RESTService" which sounds more or less like a "marker" interface. It's more common throughout OSGi to use a service property for that, if necessary at all. What I'm wondering is the following: if some service is exposed as a REST service, will it be *only* exposed as a REST service or will there also be a "normal" OSGi service in the service registry. This "normal" service probably has a different API that might not be REST-like but more Java-style. However, imagine an implementation A that publishes itself as an OSGi service S, then we could simply annotate the implementation A with the JAX-RS annotations. Tracking all services we can still pick up those annotations and we would neither need marker interfaces, nor special service properties (even though we could consider the latter to make it more explicit that some service also should be exposed as a REST service). > - Package the RESTService interface and JAX-RS classes in each > bundle that wants to expose a REST service and export as well as import the > RESTService interface package (note that each RESTService will export and > import this same package, including the Wink application bundle) That is the other possible alternative, even though I would leave RESTService out and just expose JAX-RS (either as a stand alone bundle exporting this package or part of every REST service, exporting and importing it to allow proper substitutability). Greetings, Marcel -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.amdatu.org/pipermail/amdatu-developers/attachments/20101008/c6df4591/attachment.html
