Important classes in Struts?

[Mathew Chen]

Hi,
About from the Action and the DispatchAction classes is there any other class which one can extend?

Thanks in advance.

Mathew

[Merrill Higginson]

It is also common to extend ActionForm.

Technically, though, you can extend any class in Struts that isn't declared as final. Struts is open-source, so you can look at the source and extend classes as needed. ActionServlet, RequestProcessor, ActionMapping, etc. can all be extended. I wouldn't recommend doing so, however, unless you're doing something that just doesn't fit into the way Struts works by default.

[Mathew Chen]

Thanks Merril for your reply.I think I missed out the LookUpDispatch class too.

Thanks again

[alan do]

DispatchAction and LookupDispatchAction both extend Action. you can extend pretty much everything like what merrill said, but consider first the reason(s) for extension.

i generally stay way from the core classes. consider using servlet filters to do generic pre-processing (e.g authentication) and post-processings (e.g applying xslt). there are properties of the struts controller that are configurable, but unknown and lead to unecessary extension (e.g setting nocache).

it is a good idea though to extend the Action classes since you can move common action codes such as the forwarding and error processings into 1 place. action form is another, but declarative form bean definitions cannot be extended (unless you customize the ActionServlet