[seam-dev] Interceptor packaging convention

[Pete Muir]

On 19 Apr 2010, at 17:03, Dan Allen wrote:

> On Mon, Apr 19, 2010 at 11:50 AM, Pete Muir <pmuir at redhat.com> wrote:
> Ok. I *think* I might get what you are talking about now - you are concerned because the interceptor has to go into the impl/ jar, not the API jar? And that therefore developers are going to forget that it is actually part of the public API? Or?
> 
> Because otherwise, I don't have a clue how putting something in this special intercept package can magically stop people refactoring... If I have
> 
> org.jboss.seam.intercept.ConversationBoundaryInterceptor
> 
> and someone renames it to
> 
> org.jboss.seam.intercept.ConversationEdgeInterceptor
> 
> it's just as broken for users...
> 
> That's a great point and now I see this so clearly. Interceptors must be considered part of the public API and a stable API is expected not to shift (for backwards compatibility reasons). It's public API because the develop must refer to the interceptors in beans.xml (according to spec, putting workarounds aside).

Yup, it's definitely part of the API! IMO it's better to ensure this properly via tests (e.g. we could add a tool like sigtest to our QA process, and verify all signature changes as part of a release).

What I didn't get about the original discussion was that somehow putting interceptors into a specific package somehow protects them from being changed - these are really orthogonal concerns - not breaking an API and what package stuff goes in.

> 
> If there is a refactoring, it must preserve backwards compatibility through delegation (Seam 2 did this to prevent similar breakage in configuration files).
> 
> So I guess the real issue at hand is...the consistent packaging of interceptors is really about making the <interceptors> element as simple as possible by making all the interceptors classes have the same number of package segments. That need may or may not be contrived. I haven't stood in the shoes of the developer yet being required to list out a bunch of interceptor classes.

It sounds contrived to me. Where does it come from? Given that a user might declare some interceptors, where does that leave them?