RE: Page Context Stack - a general solution to the problem ofreturning to your start page

[Marco Tedone <m_...@hotmail.com>]

We had the same problem in my project. We solved by implementing an XML
configuration file showing the relevant actions for visited page. In few
words it works like this:

1) When needed (in our case it means when an application exception is
thrown) we retrieve the last page visited by the user (like
/appname/login.jsp)
2) With this value, we match what we called a 'relevant action' to
forward the user to (generally defined in global forwards)

The XML configuration file looks like the following:

<?xml version="1.0" encoding="UTF-8"?>

<xmlop>

  <action>
    <lastPage>xml-op/Login.jsp</lastPage>
    <relevantAction>LOGIN</relevantAction>
  </action>

  <action>
    <lastPage>xml-op/Page.jsp</lastPage>
    <relevantAction>PAGE</relevantAction>
  </action>

</xmlop>  

Where the value of <relevantAction> represent a forward in struts. We
loaded the XML configuration info at startup asking help to a Struts
PlugIn and to commons-digester; now you can define a general Action
(let's say MyForwardAction) which retrieves from the request the last
page visited (xml-op/Login.jsp, where xml-op is the name of the
servlet-mapping) and then sets a mapping.findForward("String") value
with the value returned by <relevantAction>. This way, even if you're
writing another configuration file, the integrity between actions in
your application is kept, even if a blocking exception is thrown.

Hope it will help,

Marco

> -----Original Message-----
> From: Cody Sherr [mailto:csherr@covalent.net] 
> Sent: 24 April 2003 19:52
> To: Struts Users Mailing List
> Subject: Re: Page Context Stack - a general solution to the 
> problem ofreturning to your start page
> 
> 
> 
> I encountered exactly the same problem in a project, and was 
> interested in your original posting. I think that workflows 
> are a common requirement in web applications. 
> 
> We implemented something similar to what you described, a 
> stack of return paths that was stored in the session that 
> could be pushed and popped when calculating the forward to return.
> 
> A drawback is that the user can navigate anywhere in your 
> application, they're not necessarily going to "pop" when they 
> leave a workflow. 
> 
> There is a workflow extension to struts. I decided not to use 
> it because it would be a large migration problem for existing actions.
> 
> -Cody Sherr
> 
> On Wed, 2003-04-16 at 12:24, Jeff Smith wrote:
> > A while back I posted a question asking if anybody had a 
> > struts-friendly solution to returning to your starting 
> location after 
> > running a wizard or chained action sequence. While struts supports 
> > this if the starting location is fixed, it doesn't seem to for a 
> > sequence that could be launched from multiple locations. (I 
> call these 
> > "floating" action sequences.)
> > 
> > I never did get a response from anyone. (I think my question got 
> > buried under a flurry of activity on more popular threads. :-)
> > 
> > So I went ahead and implemented something that seems to work fairly 
> > well. In fact, I generalized the problem to that of creating a page 
> > context stack, with push and pop capabilities. Using this, 
> in theory, 
> > one could even implement nested wizard processes using multiple 
> > floating sequences - pushing page contexts on the way in 
> and popping 
> > them on the way out. And the best part is that you still use 
> > struts-config.xml to specify the chains.
> > 
> > The problem is, I still don't know if I've re-invented a 
> wheel here. 
> > Would this be useful to anybody else?
> > 
> > Jefficus
> > 
> > 
> > 
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> > 
> 
> 

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