RE: beans and JSPs and stuff...

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

Yeah, I know it sounds simplistic, Brad.  And it's hard to explain sometimes - 
I almost can't explain it myself.

You see, my widgets themselves do the update.  All the servlet does is tell the 
widget to update itself.  It needs no knowledge of the database; all that 
knowledge is encapsulated in the widget object.  Why is this important?  
Because I can write generic servlets that process the widgets.

For example, I currently have a system that maintains four files via the web.  
All four files are maintained by the exact same servlet.  All I do is pass it a 
server ID in the HTTP Request (a hidden field in my form) and it automatically 
creates a widget that wll update that file.  I recently added a fifth file to 
the database - the servlet will not change!  At all!  When the Factory object 
creates the Server object, all the information is encapsulated.  When I then 
create a Widget from the Server, the Widget knows which Server it is talking 
to.  The servlet then simply takes the HttpRequest data, and passes it to the 
Widget, who in turn communicates with the appropriate server.

You can do something similar in CGI, but you'll have to have SOME code 
SOMEWHERE that checks to see which server needs to be called.  That work is 
done for me automatically through inheritance and polymorphism.  This is the 
essence of OO.

Tonight I'll try to post an example servlet, but just to give you an idea, my 
servlets are roughly 20 lines of code.  Their only purpose in life is to take 
the HttpRequest and pass it to the widget, who then does what he needs to do.  
The servlet then passes control to the next JSP.

Joe



---------- Original Message ----------------------------------
From: "Stone, Brad V (TC)" <bvstone@taylorcorp.com>
Reply-To: JAVA400-L@midrange.com
Date: Wed, 28 Feb 2001 09:20:45 -0600

>>  And finally, CGI is output-only - my widgets also 
> support the update
> of data using the data input on the form, with pretty much no 
> code in the
> servlet.

Joe,

I don't follow this statement.  Are you saying that CGI programs can't
update files, can't read forms, etc?  I'm sure some of my CGI programs
update files using data read from input forms.  And not much code to it
either.

Brad
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