Re: [Resteasy-developers] Issue with Resteasy JAX-RS and interfaces

[Bill B. <bb...@re...>]

Andreas Holstenson wrote:
> Hello,
> 
> I have recently started testing Resteasy JAX-RS. I'm extremely happy so far,
> but I have run into a few problems. I have a application that was working
> with Jersey that is now deployed on Resteasy. The problem here is the
> following:
> 
> I have a method in my root resource that returns an interface called Device
> such as:
> 
> @Path("{id}")
> Device getDevice(@PathParam("id") String id);
> 
> The device interface in turn has JAX-RS annotations on it:
> 
> interface Device {
>        @GET
>        Device getSelf();
> }
> 
> The device implementation have several implementations that each one have
> different JAX-RS resource. My problem is that it seems to be impossible reach
> those resources as it seems that Resteasy always works against the interface
> for lookups.
> 

I need more information on this.  The spec says that either you put your 
annotations on an interface or on the class/superclass and not both. 
Can you show me more pseudo code?

So derivatives of Device are returned from getDevice()?  The problem 
with this is a performance one.  Resteasy would have to calculate and 
introspect and match the request on every single request.  There would 
be no way to optimize.

I guess I'll have to support it...  I'll see what I can do today and get 
out a new release.


> Is this the intended behavior? I don't remember what the JSR says about this,
> but it worked fine with Jersey.
> 
> Also on a related note it seems that MessageBodyWriter.isWriteable(Class,
> Type, Annotation[]) gets passed the declared type of the method instead of
> the actual class of the return value. This caused problems with JAXBProvider
> as my concrete implementations had a @XmlRootElement annotation but the
> actual Device implementation did not.
> 

Well, I'm in a quandry with this one.  Reason?  Generic types.  Say you 
want to write a multipart provider that matches on List<String>?  it is 
impossible to determine the generic type of the object.

I switch it to matching on the returned entity's class.

Bill

-- 
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com