[webbeans-dev] Java EE resource injection

Folks, it's time to address the problem of generalized Java EE resource injection. Web Beans needs to support injection of the following kinds of things: * EE resources (e.g. JDBC datasources, etc) * remote EJB references * web service references I believe we can treat all three as essentially the same kind of thing in the spec. Let's call it a "EE resource reference", or whatever. It's a new "kind" of Web Bean in Chapter 3. This functionality should not impact any other part of the specification. (An additional complication is that we need to unify the current notion of a "JMS endpoint" with this functionality. I don't believe that this is a difficult problem, we just need to make it a special case of a "EE resource reference", that supports additional semantics.) I see two possible paths we could go down here: Option 1: ======= The spec could simply say that for every "EE resource reference" defined in web.xml or ejb-jar.xml, that a Web Bean exists with deployment type @Production and no name. The scope and binding types of this Web Bean have the usual defaults (@Depenent, @Current), but these may be specified explicitly in web.xml or ejb-jar.xml: <ejb-ref> <ejb-ref-name>foo</ejb-ref-name> <remote>org.myapp.FooRemote</remote> <binding>org.myapp.Bar</binding> <scope>javax.webbeans.Conversation</scope> </ejb-ref> <resource-ref> <res-ref-name>jdbc/DefaultDS</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> <binding>org.myapp.Default</binding> </resource-ref> <service-ref> <service-ref-name>service/FooService</service-ref-name> <service-interface>org.myapp.Foo</service-interface> <wsdl-file>META-INF/wsdl/FooService.wsdl</wsdl-file> <jaxrpc-mapping-file>META-INF/foo-mapping.xml</jaxrpc-mapping-file> <binding>org.myapp.Bar</binding> <scope>javax.webbeans.Request</scope> </service-ref> The lifecycle of this Web Bean would be super-simple: * Bean.create() would be equivalent to a JNDI lookup for the resource * Bean.destroy() would simply discard the reference There is just one problem with this approach: EE resource references are by nature scoped to a particular EE module, whereas this is not naturally the case for Web Beans (which are naturally EAR scoped). I don't believe this is a really big problem but we would need to institute an additional layer of validation to ensure that injection points that refer to an EE resource are in the same module as the resource ref declaration. This would be a new section in the spec, but I don't believe it is difficult to write. Option 2: ======= The second option would be to require explicit declaration of the resource in web-beans.xml, thus making them an EAR-global declaration. <ResourceRef jndiName="....."> <myapp:Foo> <myapp:Bar/> </myapp:Foo> <ResquestScoped/> </ResourceRef> There are a couple of major problems with this: * resources must be declared twice, in different places * the two declarations are correlated via a global JNDI name, which: - is still not really a well-defined construct in the EE spec - cannot be properly validated at development time Therefore I strongly prefer Option 1. WDYT? -- Gavin King gavin.king(a)gmail.com http://in.relation.to/Bloggers/Gavin http://hibernate.org http://seamframework.org