Some people start to use the Actions as finely-grained business actions. For example, they want to accomplish a "move" by forwarding to a "copy" Action and then have the copy Action forward to a "delete" Action. So the point of forwarding to the next Action not to complete the response, as contemplated by the architecture, but to continue the business transaction. In essence, they try to use Actions to create a Chain of Responsibility. IMHO, that's out of scope for an Action class.
It is true that we ask too much of the Action class. In fact, we have been discussing the idea of adding another "View" handler class, or a
"page controller", to the ActionForward. The idea being that the Action might nest a call to this class (when specified) as part of the FindForward sequence. The View class could then prepare the request for whatever page it is designed to service.
Tying it to the FindForward sequence keeps the calls to the business layer within the Action lifecycle, but allows for a separation of concerns. The Action class can focus on the core business transaction, and the View class can focus on preparing the request for its server page -- once the core transaction is completed and the ActionForward is ready to be selected.
http://www.mail-archive.com/[EMAIL PROTECTED]/msg18629.html
It's just a matter of some interested party coming up with an implementation for other people to try.
For the other usage, where people have trouble creating a finely-grained business API, there's a new Chain package in the Commons sandbox that can help. This package makes it easy to chain together arbitrary units of work, so that you can do things like create a "move" command by chaining a "copy" command to a "delete" command -- and still use "copy" or "delete" on their own.
-Ted.
Derek Richardson wrote:
I was trying to avoid rehashing old arguments about action chaining. I have heard two arguments: one, it is not supported and can cause strange results and, two, it is indicative of bad design (the argument made below).
I disagree that action chaining is always indicative of bad design. See my email on the users list (that got no discussion, which I never understood) http://marc.theaimsgroup.com/?l=struts-user&m=104370639426791&w=2. I believe I made an original argument for action chaining being almost required in a particular situation.
In any case, I am not trying to force the committers to make action chaining easier in the vanilla struts distribution. I was merely hoping to get feedback if there is an obvious problem with my approach.
Perhaps I should have posted to the users list - I thought that, since this deals with modifying the framework instead of just implementing within it, that I'd get better feedback here.
Thanks,
Derek Richardson
--------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
