Manisha Menon wrote:
> Hi Craig,
>
> Exactly ! We have done in the same way.
>
> 1. Getting the action name from the hidden field.
> String action_name =
> request.getParameter("ACTION_NAME");
>
> Then instantiating the business object in either of
> the following ways.
>
> a) BusinessInterface businessObject = (BusinessObject)
> action_name;
>
> b) BusinessInterface businessObject =
> BusinessObjectfactory.createBusinessObject(action_name);
>
> But I would like to know from you, whether this
> approach is not running short of anything ?
>
> I have seen few of the approaches made use of event
> delagation methodology. Can someone explain that
> methodology in web context and also a possible
> comparison between the two ? I am sorry if I am trying
> to bring something unusual here.
>
> Thank you foryour replies,
>
> Manisha
>
This doesn't directly address your questions, but you might want to take a look at
the Struts framework at <http://jakarta.apache.org/struts>, which provides a
fleshed out framework for the MVC controller servlet and action dispatcher, plus
some nice support for dealing with forms and internationalized applications through
a JSP custom tag library.
For simple applications, I implement my business logic in the action class that
gets invoked by the controller servlet. For more complex needs, I think of the
action class as following the "adapter" design pattern, translating the HTTP
request parameters into appropriate property setter calls on business logic beans
(either EJBs or regular JavaBeans). The business logic beans, then, are insulated
from the fact that they were invoked in a web application, so you can reuse them
elsewhere.
Craig McClanahan
>
> --- "Craig R. McClanahan"
> <[EMAIL PROTECTED]> wrote:
> > Manisha Menon wrote:
> >
> > > Hi all,
> > >
> > > I know the question is very silly, but I am sorry
> > I
> > > could not avoid asking your help.
> > >
> > > I follow the MVC design methodology in my web
> > > framework which has got servlets, jsp and beans.
> > >
> > > JSP page forwards the request to the controller
> > > servlet requesting for a certain action.
> > > The servlet controller after receiving the request
> > > object,instantiates the appropriate
> > > business bean, which will use connection pool
> > manager
> > > and data access beans for manipulating
> > > the data. After completing the data handling
> > > operations, the servlet
> > > controller returns the manipulated data back to a
> > new
> > > JSP page.
> > >
> > > Now my question :
> > >
> > > How is the conversion/ translation of the action
> > (say
> > > for example updation, insertion or deletion) which
> > is
> > > coming from the client JSP page done by the
> > controller
> > > servlet taken to the
> > > right instance of business bean ? A single page
> > may
> > > have more than one action. Now, how do the
> > controller
> > > servlet calls the UpdateBusinessBean for update
> > action
> > > and InsertBusinessBean for insert action ? The
> > method
> > > that will be used by the client to invoke the
> > servlet
> > > is "POST". Can I ask you, what are the possible
> > ways
> > > of doing this, (Already I have adopted one method
> > in
> > > my last assignment, but I am not too happy about
> > it,
> > > as it did not consider scalabilty issues and also
> > it
> > > was tightly coupled.)
> > >
> > > Manisha
> > >
> >
> > In a "database maintenance" application like what
> > you describe, it is common to
> > have a single action class that is called upon to
> > perform slightly different
> > actions (such as an INSERT for a new row, or an
> > UPDATE for a second).
> >
> > What I often do in such situations is include a
> > hidden field in the input form that
> > says one of the following things:
> >
> > <input type="hidden" name="action"
> > value="Create">
> > <input type="hidden" name="action"
> > value="Delete">
> > <input type="hidden" name="action" value="Edit">
> >
> > depending on which action the user originally asked
> > for. That way, the action
> > class knows what to do, based on calling:
> >
> > request.getParameter("action")
> >
> > to see what was included in the form.
> >
> > For cases where the user doesn't select which action
> > to perform until the form is
> > submitted, this field could be set in a JavaScript
> > function, or be chosen by which
> > submit button was pressed.
> >
> > Craig McClanahan
> >
> >
> ===========================================================================
> > To unsubscribe: mailto [EMAIL PROTECTED] with
> > body: "signoff JSP-INTEREST".
> > Some relevant FAQs on JSP/Servlets can be found at:
> >
> > http://java.sun.com/products/jsp/faq.html
> > http://www.esperanto.org.nz/jsp/jspfaq.html
> > http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
> >
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
>
> __________________________________________________
> Do You Yahoo!?
> Send instant messages with Yahoo! Messenger.
> http://im.yahoo.com/
>
> ===========================================================================
> To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
> Some relevant FAQs on JSP/Servlets can be found at:
>
> http://java.sun.com/products/jsp/faq.html
> http://www.esperanto.org.nz/jsp/jspfaq.html
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
> http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
===========================================================================
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
