Re: Program Flow

[Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>]

Aaron Bartell wrote:
> JSF has some nice features for event notification (and redirection) where
> you can simply tie a button to a Java method and when clicked it goes right
> to that method.  From there the Java programmer has access to globally
> defined variables (where I store my state sometimes) and can determine where
> to go next based on the string value returned from the method (i.e. return
> "success" will check the faces config file for a mapping of the literal
> "success" to an actual page name like page123.jsp)
>   
It's interesting that you present these together.  Personally, I love 
the ability to link a button to a method, and absolutely despise the 
idea of returning a value which is compared to an XML file to determine 
the next page.  Me, I'd rather the program was able to determine the 
next page directly and forward to it, especially if it needed to add 
parms to the URL.  In JSP, you do this with 
getRequestDispatcher().forward() call and I've always loved that 
technique.  I mean, if you really want to use a configuration file, then 
by all means have a method that accesses the configuration file and 
returns a URL and then forward to it.  But I've always hated (loathed, 
despised) the idea of an application configuration file.

And the EGL folks seems to agree; since they support both the ability to 
tie a button to a function and the ability to forward to another page.  
I'm not certain what they do about the idea of a configuration file and 
being able to return a value to determine the next page; in EGL you just 
execute a "forward" opcode.  But the button business is even easier.  
When you define a function in a page handler, it's visible on the 
WYSIWYG editor's Page Data view, and you can then just drag that onto a 
button; that binds the button to the function.

Navigation in most of my applications is based on hyperlinks in the page 
(for things like drilldowns).  You create a table and then link it to a 
URL.  You add a link attribute to just about anything, and then you can 
modify the link to use data from the page.  That could be fields, hidden 
fields, even columns in a table.

You can do something similar for AJAX requests.  You define an area that 
is AJAX capable, then you bind an AJAX refresh request to an event (such 
as clicking a button or a table cell).

Joe