General feedback, comments and questions

Question

Background: Written many web applications over the years (Java [cocoon, struts, home-grown frameworks], ISAPI, cgi-bin), and also worked with RAD tools like Delphi doing client/server apps. Consequently, JSF looks very interesting to me, especially when you consider .NET and Web Forms. Here are my comments/questions:
-     The name �Request Events� is confusing. Should be �UI State Change Events� or something.
-     Why isn't there a subclass of FacesEvent for �Request Events�?
-     Are there any standard events that all components respond to? (i.e page lifecycle events)
-     Is there anyway to explicitly state that a component responds to specific types of events (like the way Validators tell you what types of attributes they respond to)? What I�d like to see is the ability to generate an Events tab in the development tool, like most modern RAD environments.
-     In order to take advantage of a central dispatching mechanism (ApplicationHandler), it would make sense for all pages to flow through the FacesServlet. Is there a pass-through mechanism that doesn�t require a response tree, or would this just be some type of application event? In other words, how does FacesServlet process requests that aren�t mapped to a component tree?
-     Can you give us an idea about how the model references will work, and what the standard way for the application handler (and its delegates) will get a handle to a model reference will be? (i.e. session parameter).
-     Why use UIParameters instead of attributes?
-     I understand that grid and table display functionality is handled by standard Renderers. I still think that JSF needs to have a more complete standard suite of components as well, including grid and table components that can be bound directly to collections and ResultSets. (I know this isn�t EJB-friendly, but in reality many servlet-based applications don�t use EJB). Just requiring a UIPanel alone and the appropriate Renderers isn�t enough. I think that in order for JSF to be successful, it must have at least the standard components that .NET does.
-     This is a minor detail, but shouldn�t there be a simple addMessage(Message message) method on the FacesContext instead of requiring you to send in null?
-     You should be able to declaratively associate an ApplicationHandler � you shouldn�t have to add a ServletContextListener to do this.
-     You should be able to specify a RenderKit for an entire application declaratively. This brings up the question of whether or not an application-wide context is needed (or if the JSF implementation should just subclass ServletContext).
-     You should also be able to specify the RenderKit for a given session as well as a specific Tree.
-     Currently, I don�t see any support for modifying the render kit in the JSP implementation. Shouldn�t this be an attribute of the <faces:usefaces> tag?
-     I�m worried about the performance implications of this design for more complex user interfaces with many controls on a given page. I�ve seen others raise this concern as well, especially when you consider the overhead of copying component values, and constantly traversing the component tree. I recognize that there are a lot of places where object pooling can be used (Renderers, the components themselves, LifeCycle objects, etc.), but does anyone have any specific comments on how this can be achieved with minimal overhead, especially when you consider that a given application may have filters and additional logic in the ApplicationHandler (that may in turn talk to the EIS tier).
I�m glad to see that for events, encoding, and decoding, you can either handle it directly in the component or delegate it to the proper handler (either a RequestEventHandler or a Renderer). This addresses the fact that in-house controls will likely be bound to a specific client device (at least originally).
In general, I think this is a great move forward, and it�s one thing that we�ve been lacking for a while (there have been many non-Sun efforts on this front for a while, but we really need a standard if Java is going to remain the preferred platform for rapidly building web apps).
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Kito D. Mann
[email protected]
Virtua, Inc.

Answer 1

In regards to my third point:
- Is there anyway to explicitly state that a component responds to specific types of events (like the way Validators tell you what types of attributes they respond to)? What I�d like to see is the ability to generate an Events tab in the development tool, like most modern RAD environments.
I just realized that this is handled implicitly by the fact that all UIComponents are JavaBeans. JavaBeans supports this via EventSetDescriptors. This is what happens when you haven't worked with any GUI tool kits (like Swing) for years :-). It'll be nice to see this functionality in the servlet world.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kito D. Mann
[email protected]
Virtua, Inc.