--- Joe Germuska <[EMAIL PROTECTED]> wrote: > Just a little "me-too" here, but I think both Ted and David have good > points. Ted's approach to adding a controller to the ActionForward > is a relatively small change to the infrastructure that can offer a > lot of gain. And I've been interested in seeing some kind of > ActionContext class for quite a while now.
I chose my words carefully when I said "ActionContext interface". I *think* we can all agree that if we added this it should be an interface :-). David > > Joe > > > At 6:47 -0700 8/11/03, David Graham wrote: > >--- Ted Husted <[EMAIL PROTECTED]> wrote: > >> David Graham wrote: > >> > What I think we're seeing here > >> > is that we've outgrown our ActionForward declarations and need > some > >> new > >> > ones. I'm fine with adding a SuccessAction but would really like > to > >> see > >> > us discuss future possibilities in this area. > >> > >> This may not be what you meant, but I've been thinking that > >> ActionForward could use a class extension point, same as > ActionMapping. > >> > >> The idea would be to give ActionForward a type property for a Java > >> class. If the property is specified, instead of just taking the path > as > >> it stands, the Controller would call a "prepare" method on the > class, > >> passing it the ActionForward, ActionForm, HttpRequest, and > HttpResponse. > > > >This may be a good time to add an ActionContext interface instead of > >passing all these individual pieces. This would also slightly remove > the > >dependence on Servlet to allow us more flexibility when we look at the > >Portlet API. > > > >> > >> The prepare method would return a String that the Controller would > use > >> for the path. > >> > >> This allows the ActionForward to act as a Page Controller for the > path. > >> If the particular page referenced by the path needs any special > "chrome" > >> > >> the Page Controller can set that up. Or, if the path needs to be > >> adjusted for Locale or device (PDA, browser, et al), then the Page > >> Controller could adjust the path before returning it. > >> > >> If it were a virtual page, like an dynamic image, merge file, or > PDF, > >> the Page class could also render the Response, rather than have the > >> Action do it. > >> > >> Right now, the Action is doing double duty. It first acts as a > >> Dispatcher that acquires business resources and selects the logical > >> view. But, in real life, many pages often need special runtime > resources > >> > >> of their own. So, the Action also serves as a Page Controller for > the > >> page it selects. Many of us consider that a mixing of concerns, and > so > >> we start to use some Actions as Dispatchers and others as Page > >> Controllers. Tiles also fills this gap and is essentially a hybrid > of a > >> Compositive View and a Page Controller framework. > >> > >> I'm thinking that, architecturally, the ActionForward represents > some > >> resource available to the application, of any type, that can be > reached > >> by the application's protocol. In an http environment, it's the job > of a > >> > >> Resource object to provide a URI that the Controller can use the > reach > >> the actual resource. (And, in another environment, perhaps the path > >> would not be a URI.) > >> > >> The Action, in its purest form, represents a Dispatcher. It's the > job of > >> > >> a Dispatcher to select which (logical) Resource will handle the > >> response. When we talk about selecting between "success", "failure", > or > >> "glockenspiel", we're talking about dispatching. > >> > >> But, in real life, we often can't just dispatch to a page. The page > >> needs certain resources to render, often to fill UI controls like > select > >> > >> lists. > >> > >> Ideally, I believe another class, specified by the ActionForward, > should > >> > >> be responsible for setting up any "chrome" a particular page may > need. > >> It's the one that knows where the page is (via the path property), > and > >> so it's the one that should be privy to these details. > >> > >> What would start to happen here, I think, is that people will put > into > >> the new class the code that now encourages them to "chain" > >> some Actions. By providing a separation of concern between "choosing > the > >> Resource" and "preparing the context for the Resource", it becomes > >> easier for people to Do The Right Thing. > > > >I've had similar composition problems and agree that a separation makes > >sense. Tiles Controllers can be used to setup page data but that > doesn't > >always work (especially if you're not using Tiles :-) so I end up > chaining > >actions. None of the action chaining is due to bus. logic as that's > >properly factored into a Service layer; it has to do purely with > setting > >up page data. > > > >Tiles Controllers are one of the major reasons I use Tiles and I think > >it's appropriate to move that concept into the Struts core. > > > >David > > > >> > >> The "gotcha" is that, to do its job, the ActionForward type may also > >> need to interact with the business layer. It doesn't seem right that > the > >> > >> Page Controller should try to branch to another page, like an Action > >> might, if there's an error. But the declarative exception handling > might > >> > >> be able to step in here. > >> > >> -Ted. > >> > >> -- > >> Ted Husted, > >> Junit in Action - <http://www.manning.com/massol/>, > >> Struts in Action - <http://husted.com/struts/book.html>, > >> JSP Site Design - > >> <http://www.amazon.com/exec/obidos/ISBN=1861005512>. > >> > >> > >> > >> > >> > --------------------------------------------------------------------- > >> To unsubscribe, e-mail: [EMAIL PROTECTED] > >> For additional commands, e-mail: [EMAIL PROTECTED] > >> > > > > > >__________________________________ > >Do you Yahoo!? > >Yahoo! SiteBuilder - Free, easy-to-use web site design software > >http://sitebuilder.yahoo.com > > > >--------------------------------------------------------------------- > >To unsubscribe, e-mail: [EMAIL PROTECTED] > >For additional commands, e-mail: [EMAIL PROTECTED] > > > -- > -- > Joe Germuska > [EMAIL PROTECTED] > http://blog.germuska.com > "If nature worked that way, the universe would crash all the time." > --Jaron Lanier > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
