Re: Design pattern needed: breaking webapp into modules

We've got a webapp that has different modules. Let's say, just as an
example, the modules are Editing, Querying, and Reporting. Each module
has its own set of JSP pages. The modules also have some sub-pages in
common like headers and footers.

We'd really like to distribute the modules independently. A customer
might buy only Editing and Querying, but not Reporting, for example.

One of the modules is open source, which means that we'd like to
distribute it as a complete, standalone project. But we'd also like to
be able to integrate it with the rest of the webapp easily.

Does anyone have a good design pattern for this? I'm struggling with how
to organize the webapp, where to put the pages, how to have independent
projects that share common pages and code, etc. Any ideas appreciated.