[Springframework-developer] Re: Support for state/controller chaining in Portlets? (not quite webflow)

[John L. <jl...@ar...>]

Tim,

What you are looking for is a way to map requests to a variety of 
different controllers all within a single portlet.  This is easily done, 
although there is not yet a standard class available for doing this in 
Spring Portlet MVC.  You need a class that decends from 
AbstractPortletControllerMapping to do this.  At least three of us have 
independently developed our own version of an "action" based mapping 
class that lets you declare a request parameter that indicates which 
controller you want to end up in.  We will work on a unified one that 
should become part of Portlet MVC soon.  In the mean time, send me an 
email directly at jl...@ar... and I will send you something 
you can use in the meantime.  Also, make sure you look at the enhanced 
classes already available on the Wiki site for a more complete set of 
controller options:

http://opensource.atlassian.com/confluence/spring/display/JSR168/


John Lewis


> -----Original Message-----
> From: spr...@li...
> [mailto:spr...@li...] On Behalf
> Of Tim Kettering
> Sent: Tuesday, May 17, 2005 4:00 PM
> To: spr...@li...
> Subject: [Springframework-developer] Support for state/controller
> chaining in Portlets? (not quite webflow)
> 
> 
> Hi everyone,
> 
> I'm just throwing this out here to see what other people have to say.  I
> can see from the list that there are a few developers actively working
> on portal solutions using Spring MVC.  We are starting on our first
> project using this as well, and one of the issues I'm trying to figure
> out now is the matter of maintaining state in a portlet. 
> 
> 
> In a typical CRUD example, if we have a portlet to display, edit and
> maange information about a certain object, like a Book. We'd have view,
> edit and delete functionality for example.
> 
> 
> In a typical non-portlet webapp, we could easily split those up across
> different servlets for fine-grained areas of responsibility. 
> 
> 
> But it's not as simple with portlets, because there are limitations on
> what can be done, and essentially, all requests would need to go thru a
> single portlet configuration. 
> 
> 
> So, it no longer become sufficient to configure a simple portlet
> controller for a portlet.  There needs to be a way to maintain state and
> to delegate the request/response process to different types of
> controllers depending on the state.  Like a View page would need to go
> thru a derivation of BaseCommandController, an Edit page would go thru
> SimpleFormController.
> 
> 
> And not to mention adding yet another dimension when considering portlet
> modes as well!
> 
> This article at IBM Developerworks pretty much covers the same issue I
> am bringing up:
> 
> http://www-106.ibm.com/developerworks/websphere/library/techarticles/031
> 2_ha
> nis/hanis1.html
> 
> I did look at Spring's WebFlow a few days ago to see if it could address
> our issue, but in the Webflow FAQ, it pretty much states that WebFlow
> should not be used in cases where the user will be using back-button, or
> indeterminate actions not within a strict flow. 
> 
> 
> So that kinda leaves me back at square one.  After some discussion with
> my co-worker, I would imagine that this is a common problem for any
> Spring portlet developer creating more than just simple portlet
> functionality.  And that as Spring portlet support matures, this will be
> a more common issue for everyone.  Hence this email to the list. 
> 
> 
> I'm now wondering how some of you have addressed this problem, and
> whether there is a need for Spring's portlet support, to be in Spring
> 1.3 to include some way to configure and facilitate a state process,
> maybe even based on WebFlow's state machine - although I have only given
> WebFlow's state functionality a brief look.
> 
> Thanks in advance,
> 
> -tim
> 
> 
> 
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