[jira] [Resolved] (CXF-4290) Allow user-specified classloader for JAXRSClientFactory

["Sergey Beryozkin (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CXF-4290?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sergey Beryozkin resolved CXF-4290.
-----------------------------------

       Resolution: Fixed
    Fix Version/s: 2.5.4
                   2.6.1
         Assignee: Sergey Beryozkin
    
> Allow user-specified classloader for JAXRSClientFactory
> -------------------------------------------------------
>
>                 Key: CXF-4290
>                 URL: https://issues.apache.org/jira/browse/CXF-4290
>             Project: CXF
>          Issue Type: Improvement
>          Components: JAX-RS
>    Affects Versions: 2.5
>         Environment: Apache Karaf 2.2.4, CXF 2.5.0
>            Reporter: Chris Dolan
>            Assignee: Sergey Beryozkin
>             Fix For: 2.6.1, 2.5.4
>
>
> I wrote a helper class that isolates CXF's JAXRSClientFactory from users. My helper exposes this interface as a OSGi service:
> {code}
> public interface JaxRsClientBuilder {
>     <T> T createClient(@Nonnull String baseUrl, @Nonnull Class<T> resourceApiClass);
> }
> {code}
> However, I discovered a blocking problem. If the user of my helper doesn't import org.apache.cxf.jaxrs.client in its OSGi classloader, then I get exceptions from java.lang.reflect.Proxy because there's no classloader anywhere that can see both resourceApiClass and org.apache.cxf.jaxrs.client.Client. I tried a solution (based on http://blog.osgi.org/2008/08/classy-solutions-to-tricky-proxies.html) where I dynamically make an aggregate classloader that can see both resourceApiClass and Client. I think I can trick JAXRSClientFactory into using this new classloader for the main resource (by passing in a new Proxy instance as the resource class), but I can't wedge my custom classloader in for subresources because of the way ClientProxyImpl.invoke() calls JAXRSClientFactory.
> I request the following as a possible solution. Certainly, I'd accept a better solution. For example, it looks like JAX-RS 2.0 should eliminate this problem by making Client into a public interface instead of an implementation detail.
>  1) add a new method variant to JAXRSClientFactory that takes a classloader
>  2) pass this classloader to JAXRSClientFactoryBean, and use it instead of cri.getServiceClass().getClassLoader() or the thread context classloader
>  3) change ClientProxyImpl to save this classloader and use it for subresources
> See also the following which describes my failed attempt to work around this issue: http://stackoverflow.com/questions/10458378/how-can-i-make-a-java-lang-reflect-proxy-from-two-separate-classloaders

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