We have an aging middleware product that integrates with some very specific legacy systems. The middleware is currently written in Java, and is now several years old. We are considering rewriting the product as our needs have expanded over the years, and the current design does not lend itself to our new needs. After looking at JBoss, we see that all of our needs are covered in the JBoss microkernel (JMX). However, the actual functionality of our middleware is not covered in any of the currently available services for JBoss, so we would have to create our own JBoss service(s). Again, we are much more interested in the JMX kernel than the JBoss services that already exist for that kernel.
What we would like to do is take the JBoss microkernel and rewrite our middleware as a series of JBoss services/modules/extensions (whatever you want to call it). What is the best way to get up to speed on developing a JBoss service? Is there documentation we can purchase that goes into details on the internal architecture of JBoss... internals that would help a developer wrap his mind around the finer details so that he could develop services for JBoss? I'm not talking about documentation for using JBoss, or documentation on developing solutions with JBoss (such as EJB tutorials and such). I am talking about documentation that would aid in developing extensions/services/modules for the JBoss platform.
The information for writing JBoss services is included in the 3.0 Admin & Development Draft, you can find it under the Documentation link.