hi craig ..
thanx for reply ...but still some confusions
intermixed ,pl.bear
i
"Craig R. McClanahan" wrote:
> piyush raj jain wrote:
>
> > hi model2 camp..
> > newly joined the camp, following the threads from past two weeks..
> > sorry if this kind of stuffs already been discussed
> >
> > i was also thinking that what is wrong if my controller will pass the control to a
> > action servlet which implements the action interface.
> > advantages:
> > 1.if i am not maintaing the hashtable of action object like craig , (just storing
> > the names and dynamically creating an object for each request , same what kevin is
> > doing ) then my action servlet will give me the benifit of servlet life cycle .
> >
>
> As I just responded to Kamalesh's post, it's probably OK to do this -- but don't
> succumb to the temptation to mix presentation logic in your action servlets. They
> should still just do the business logic and forward to JSP pages for output. ((NOTE
>--
> in all cases where I have been saying "use JSP pages" for output, you could also use
> servlets based on some nice template mechanism; but I find JSP easy and its very
>widely
> supported))
>
> My action classes tend to be 50-150 lines of code -- nearly all of which is copying
> HTTP parameters into bean properties, calling bean business methods, and storing
> results. I haven't ever found any need to have lifecycle support for them.
>
> >
> > 2.through servletcontext i can access the application level objects while
> > processing my logic in action class,and once controller will pass me the
> > resposibilty i will never ask controller to do any thing else, all further
> > processing will be done by second level action servlet .This can give me cleaner
> > architecture.
> >
>
>=========================================================================================
>
> As long as you don't map your action servlet to its own URL. If you do, you're going
> to tempt page designers to bypass your controller servlet and go directly to the
> "right" action servlet. This is one more subtle linkage between presentation logic
>and
> business logic that you want to think about.
i understand that i should not leave any possibilties of bypassing the controller
servlet .
But when we talk about subcontroller action servlets for an application with multiple
domains--
suppose right now i am desigining an integrated application for a company which has ten
different divisions and work domains, later my application can grow and i may be
interested
to break it in individual servers even at different locations, at that time i hope
that if
i have independent subcontrollers for domains i just need to detach my subcontroller
from
the application and promote him to controller level.
=========================================================================================
thanx in advance
piyush
>
>
> >
> > 3.If i can divide my application in number of different domains then i can call
> > these servlets as a subcontroller, which will act as a controller for a particular
> > area of application.
> >
>
> That's certainly possible -- you could do the same thing by having subcontrollers
>that
> still used action beans if you wanted to.
>
> >
> > 4.request can be fulllfilled by multithreded architecture of servlet engine (i need
> > not to do the thread programming in my actiion classes .)
> >
>
> Here is where I think you are going to be unpleasantly surprised. The multithread
> environment issues apply just as much to the "action servlet" design pattern as they
>do
> to "action beans", because there's only one instance of the action servlet class --
> exactly like I only create one instance of the "action bean" class of any particular
> type.
>
> There's a ***partial*** workaround in the servlet API -- if your servlet implements
>the
> SingleThreadModel interface, the servlet container guarantees that it won't call that
> particular servlet instance on more than one thread at the same time. However, you
>are
> not out of the woods -- there are lots of cases where the same user can cause more
>than
> one request to be in progress at the same time, so you *still* have to deal with
> multithread impacts on all your beans.
>
> >
> > thanks
> > piyush
> >
>
> Craig McClanahan
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