[jboss-dev-forums] [Design the new POJO MicroContainer] - Re: Obtain Kernel from unspecified Context (Repost)

"ALRubinger" wrote : | What are the fundamental arguments against the following construct: | * Security - if you have two kernels in the same JVM with an api to get access to both, how do you stop one user playing with the other user's kernel? * API - why is name appropriate? e.g. for scoped kernels we use a scope key since the kernels are not independent and have a structure * An invalid assumption in your argument anonymous wrote : | However, this introduces a precondition that all POJOs with dependencies on MC Beans are installed into the MC itself. In many cases, this is not possible. | There are at least four ways to inject objects that are not managed by the MC. 1) Using a factory (the factory knows how to get a reference to the object and it is then registered in the MC) 2) Using a value-factory (a more general approach where the object is not registered in the MC - e.g. this can be used to inject things like system properties or get information from an ldap server, etc. 3) Inject a locator - this is like (2) but less declartive. You inject an object that can be used to locate the relevant object in some arbitrary way 4) Using a KernelRegistryPlugin - maps some other "namespace"s into the MC injection namespace * Philosophy This isn't pure IOC. You now depend upon the API and not just that, you have to agree a name which probably isn't going to work in some arbitrary environment. e.g. look at the horrible hack where we locate the MBeanServer by seeing which has a default domain of "jboss" - which isn't even necessarily unique The kernel is only really required for specialised cases where some component wants to manage the state of another component. e.g. the service controller managing jmx lifecycle or the deployers managing the deployment lifecycle Other uses are generally hacks because you haven't thought out how to do IOC properly. * Summary In general the building of such a registry is something a user can do according their usecase. e.g. in the appserver the singleton kernel can be located using ServiceController.getKernel(). But there's nothing to stop a web-app creating its own kernel for its own internal use. The retrieval/availablity of the relevant kernel(s) is best left whoever created it, since only they know how it should be used. But this is really for "super users", most users should use plain IOC. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4151442#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...