Re: [weld-dev] @Resource annotation handling by Weld vs Servlet container

> Looking at the WeldServletLifecyle class on line 124, it will always > provide an implementation of the ResourceInjectionServices (an > instance of ServletResourceInjectionServices). If we were to provide > our own implementation of ResourceInjectionServices, how would we > override that one? Is there a way to get a hold of the Deployment and > thus the BeanDeploymentArchives so we could set our own implementation > up? Ideally we'd like a pure CDI api way of interacting with weld, but > maybe that's not possible in this case? You need to interact with Weld APIs to do this. A service can be overridden using ServiceLoader mechanism. See http://docs.jboss.org/weld/reference/2.2.10.Final/en-US/html/ri-spi.html#... for details.

> Alternatively, instead of Weld >> >> hooking into lifecycle of Jetty-managed components, Jetty could use CDI >> APIs >> to perform CDI injection on instances it manages. >> > Yes, potentially we could do that, although we'd probably need your > guidance on the best way to do that. Can @Resource be used by pojo > beans or only by servlet artifacts (servlet/filter/listeners)? If the > latter, then I'm fine for Jetty to do all the handling of @Resource. > If not, then it probably makes sense for weld to handle it, and we'd > need a way to disable Jetty's implementation if weld is present in a > webapp ... I think the best approach would be to modify the integrating decorator to only provide CDI injection to Jetty-managed instances. I have implemented it here: https://github.com/weld/core/commit/f7420e34355c5c82ef516713c65fc6cd750fb651

> > cheers > Jan > >> Additional comments inline: >> >> >> On 04/10/2015 02:00 AM, Jan Bartel wrote: >>> >>> Hi Weld developers, >>> >>> The Jetty project is looking at how we can do a tighter integration >>> with Weld, also with a view to discussions in the Servlet Spec 4 >>> committee to alleviate the necessity for CDI implementations to >>> maintain jetty-specific initialisation code. >>> >>> During investigations, I noticed that we seem to have a conflict in >>> the handling of a few annotations for classes that are managed by the >>> servlet container (ie servlets, filters, listeners etc): >>> >>> @Resource >>> @PostConstruct >>> @PreDestroy >>> >>> As Jetty puts a servlet/filter/listener into service, we introspect >>> the class and find the above annotations and process them. It seems >>> that Weld does too, as I see the following failure for this code >>> snippet: >>> >>> public class TestListener implements ServletContextListener >>> { >>> @Resource(mappedName="maxAmount") >>> private Double maxAmount; >>> } >>> >>> >>> javax.naming.NameNotFoundException; remaining name 'maxAmount' >>> at >>> >>> org.eclipse.jetty.jndi.local.localContextRoot.lookup(localContextRoot.java:429) >>> at >>> >>> org.eclipse.jetty.jndi.local.localContextRoot.lookup(localContextRoot.java:533) >>> at javax.naming.InitialContext.lookup(InitialContext.java:411) >>> at >>> >>> org.jboss.weld.injection.spi.helpers.AbstractResourceServices.resolveResource(AbstractResourceServices.java:48) >>> at >>> >>> org.jboss.weld.injection.spi.helpers.AbstractResourceServices$1.createResource(AbstractResourceServices.java:121) >>> at >>> >>> org.jboss.weld.injection.AbstractResourceInjection.getResourceReference(AbstractResourceInjection.java:44) >>> at >>> >>> org.jboss.weld.injection.AbstractResourceInjection.injectResourceReference(AbstractResourceInjection.java:53) >>> at org.jboss.weld.util.Beans.injectEEFields(Beans.java:344) >>> at >>> >>> org.jboss.weld.injection.producer.ResourceInjector$1.proceed(ResourceInjector.java:69) >>> at >>> >>> org.jboss.weld.injection.InjectionContextImpl.run(InjectionContextImpl.java:48) >>> at >>> >>> org.jboss.weld.injection.producer.ResourceInjector.inject(ResourceInjector.java:72) >>> at >>> >>> org.jboss.weld.injection.producer.BasicInjectionTarget.inject(BasicInjectionTarget.java:121) >>> at >>> >>> org.jboss.weld.environment.servlet.inject.AbstractInjector.inject(AbstractInjector.java:55) >>> at >>> >>> org.jboss.weld.environment.jetty.JettyWeldInjector.inject(JettyWeldInjector.java:15) >>> at >>> >>> org.jboss.weld.environment.jetty.WeldDecorator.decorate(WeldDecorator.java:105) >>> at >>> >>> org.eclipse.jetty.util.DecoratedObjectFactory.decorate(DecoratedObjectFactory.java:77) >>> at >>> >>> org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:335) >>> at >>> >>> org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1349) >>> at >>> >>> org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1342) >>> at >>> >>> org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:743) >>> at >>> >>> org.eclipse.jetty.servlet.ServletContextHandler.doStart(ServletContextHandler.java:257) >>> at >>> org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:505) >>> >>> >>> Googling around, it is not clear to me exactly which of the Common >>> Annotations (JSR250) that Weld supports and I'd appreciate some input >>> from the Weld devs in order for Jetty to work out how best to move >>> forward with Weld integration. >>> >>> In particular, I'd appreciate some clear feedback on which of the >>> following @Resource annotation usages will be handled by Weld: >>> >>> @Resource on a class >>> @Resource on a field >>> @Resource on a method >>> @Resource annotations without an accompanying @Producer annotation >> >> @Resource on a field (with or without @Producer), @Resource on a method, >> @PostConstruct and @PreDestroy are handled by Weld on a managed instance >> (generally). >>> >>> >>> Secondly, as can be seen from the stacktrace above, Weld is failing to >>> find the matching JNDI entry for an @Resource annotation. This is >>> because Weld appears not to be looking in "java:comp/env" namespace, >>> although IIRC that is mandated by the JavaEE spec for EE managed >>> classes (servlets/filters/listeners etc). So if Jetty delegates >>> handling of some/all processing of @Resource, how do we ensure that >>> Weld will be able to find the right JNDI entry? >> >> This might be a bug in weld-servlet's ResourceInjectionServices >> implementation. Can you file an issue at >> https://issues.jboss.org/browse/WELD ? >> >>> thanks for your time, >>> Jan >> >> > >