I don't think anyone was suggesting putting all the functionality into a
single class. Rather, the idea is to put all of the functionality under the
control of a single servlet. This servlet then implements the Controller
role in the MVC pattern.
Take a look at the Struts framework (http://jakarta.apache.org/struts) for
an excellent example of how his can be done.
--
Martin Cooper
Tumbleweed Communications
At 11:29 AM 9/12/00 +0200, you wrote:
>Hi,
>
>IMHO squeezing a big chunk of your application's functionality into one huge
>class breaks some fundamental OO design principles. Good OO designs usually
>have a lot of medium or small "coherent" classes rather than a few very big
>ones which contain unrelated data or functionality. This makes it easier to
>use OO techniques such as encapsulation and inheritance to achieve goals
>like re-use, ease of maintenance etc.
>
>There are plenty of resources out there to learn more about OO design...
>
>I think that it can be difficult to achieve a good OO design with servlets,
>which are inherently functionally-orientated, but one possible way to deal
>with the problem in the original post is to define a 'handler' servlet which
>is a super-class of all handler servlets in the application. This can define
>common functionality such as error handling, input validation, checking
>security permissions etc. This would still mean a separate (servlet)
>sub-class for each web-page but this is not necessarily such a bad thing.
>After all, there are plenty of ways of managing large numbers of class
>files, like the package mechanism built into the language as well as
>sophisticated IDE's etc.
>
>Oisin
>
> > -----Original Message-----
> > From: Ryan Richards [SMTP:[EMAIL PROTECTED]]
> > Sent: Tuesday, September 12, 2000 5:23 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: SV: Design Question
> >
> > Thanks to all for there responses.
> >
> > Matthias:
> >
> > I can see your point and it is interesting indeed. Basically
> > instead of using one Servlet you combine all the processes
> > into one servlet and have each form utilize that servlet
> > .... hmm very interesting. I will go with that. Thanks!
> >
> > Ryan
> >
> >
> >
> >
> > -----Original Message-----
> > From: Matthias Carlsson
> > [EMAIL PROTECTED]
> > Sent: Mon, 11 Sep 2000 19:07:28 +0200
> > To: [EMAIL PROTECTED],
> > [EMAIL PROTECTED]
> > Subject: SV: Design Question
> >
> >
> > Although I don't know if it is an effective approach, this
> > is how I
> > (usually) solve this kind of problems (and since I'm used to
> > it, I
> > find it effective).
> >
> > Since I don't like having lots of classes, I create one
> > servlet, say
> > FormHandler. When I call this servlet, I also include a
> > parameter
> > telling me which form it was called from. This check is done
> > in it's
> > doPost method, and the correct doPost is then called. See
> > example
> > below:
> >
> > import java.io.*;
> > import javax.servlet.*;
> > import javax.servlet.http.*;
> >
> > public class FormHandler extends HttpServlet {
> >
> > public void doPost(HttpServletRequest request,
> > HttpServletResponse
> > response)
> > throws ServletException, IOException {
> >
> > String caller = request.getParameter("caller");
> > if (caller.equals("form1")) doPostForm1(request,
> > response);
> > else if (caller.requals("form2")) doPostForm2(request,
> > response);
> > ... and so on
> >
> > }
> >
> > private void doPostForm1(HttpServletRequest request,
> > HttpServletResponse
> > response)
> > throws ServletException, IOException {
> > // handle form data sent from 'form1'
> > }
> >
> > private void doPostForm2(HttpServletRequest request,
> > HttpServletResponse
> > response)
> > throws ServletException, IOException {
> > // handle form data sent from 'from'
> > }
> >
> > }
> >
> > This way, you can easily add new forms to be handled to the
> > servlet, and you
> > won't
> > have to keep track of several source files, and their class
> > names.
> > Hope this helps.
> >
> > [ Matthias Carlsson ]
> > [ Programmer (Java, CGI/Perl, Javascript, HTML) ] [ Web
> > Designer ]
> > [ E-Mail : [EMAIL PROTECTED] ] [ ICQ:
> > 1430647 ]
> >
> > -----Ursprungligt meddelande-----
> > Fran: A mailing list for discussion about Sun Microsystem's
> > Java Servlet
> > API Technology. [mailto:[EMAIL PROTECTED]]For
> > Ryan Richards
> > Skickat: den 11 september 2000 15:43
> > Till: [EMAIL PROTECTED]
> > Amne: Design Question
> >
> >
> > I have a web site that uses several servlets to capture and
> > utilize html form data and extract or insert into a database
> > based on the form etc...Each form has it's own servlet that
> > does the functionality. The only difference between them is
> > of course th form elements and the jdbc queries/operations.
> >
> > My question is this: Should I be looking at a specific
> > design pattern or some other means to get away from using a
> > specific servlet for EVERY html form? I feel like I am doing
> > a half-baked approach here and would appreciate any
> > ideas/comments/etc..
> >
> >
> > Ryan
> > __________________________________________________________________________
> > _
> > Visit http://www.visto.com/info, your free web-based
> > communications center.
> > Visto.com. Life on the Dot.
> >
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> >
> >
> >
> >
> >
> >
> > __________________________________________________________________________
> > _
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> > center.
> > Visto.com. Life on the Dot.
> >
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