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Posted to user@struts.apache.org by Mark Jones <te...@markjones.ukf.net> on 2004/02/22 05:40:35 UTC
[Newbie] Is it worth subclassing your own Action and ActionForm classes to attain code re-use?
My application allows a user to make various different types of bookings for
a (fictional!!!) hospital and logs them in a database. Each type of booking
has a set of common properties but also different ones depending on the type
of booking being made.
I have divided my classes into a BookingAction and BookingActionForm
superclass and subclasses (such as AmbulanceBookingAction and
AmbulanceBookingActionForm) because I anticipate creating other subtypes of
BookingAction that use the same properties in the BookingAction class but
not in the AmbulanceBookingAction subclass. This initially seemed to me to
be in keeping with programming for code re-use and extensibility.
My problem with this is, if a user submits a form which posts its data via
the ActionServlet to the AmbulanceBookingAction subclass, how would I ensure
the BookingAction class did its stuff? Would it be better / easier to use
separate, non-derived (from my superclasses) Actions and ActionForms to
handle each type of booking and not subclass BookingAction and
BookingActionForm (even though I would be repeating the some of the same
properties common to each different type of booking)?
I am concerned, though, not to lose points for not reusing code. It just
seems to me, though, that trying to divvy the handling of the form data via
inheritance is too complicated and / or unnecessary.
In what circumstances might you want to subclass your own Action class and,
if you did, how would you handle/inherit the form data? Would you just use
different subclasses of your Action but just one ActionForm for each Action?
What is the best way for me to implement this problem? (Or have I answered
my own question?! ;0) )
Thanks for indulging me!
Mark
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RE: [Newbie] Is it worth subclassing your own Action and ActionForm classes to attain code re-use?
Posted by Matthias Wessendorf <ma...@matthias-wessendorf.de>.
Hi Mark,
like Adam said, i also have one "super-action-class" :-)
i declare it as abstract an implement execute()-methode
form Action
inside execute(), i call an abstract methode (e.g. doExecute())
so our ActionServlet(it´s RequestProcessor...) calls execute()
and every subclassed doExecute().
there is a "sample-code" below:
instead of ActionForm-Klasses i also use DynaActionForms.
but i use DynaValidatorForm for using Validator-Framework.
<form-bean name="logonForm"
type="org.apache.struts.validator.DynaValidatorForm">
<form-property name="user" type="java.lang.String" />
<form-property name="password" type="java.lang.String" />
</form-bean>
i use PropertyUtils.copyProperties()
(from the nice jakarta-commons-beanutils-project)
inside an action.class to get the form-properties:
PropertyUtils.copyProperties(myDataTransferObject,form);
it copied all properities from form to your business-objects
if the props are named equal!!
for "manually" access
you have to use
Integer integer = (Integer)form.get("ageOfMisterX");
form.set("ageOfMisterX",new Integer("33"));
because all properties are savaed in a HashMap
hope that helps.
cheers
Matthias
----------------------------------------------------
public abstract class SuperAction extends Action{
public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception {
//do common things
return doExecute(mapping,form,request,response);
}
public abstract ActionForward doExecute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception;
}
-----Original Message-----
From: Adam Hardy [mailto:ahardy.struts@cyberspaceroad.com]
Sent: Sunday, February 22, 2004 12:15 PM
To: Struts Users Mailing List
Subject: Re: [Newbie] Is it worth subclassing your own Action and
ActionForm classes to attain code re-use?
On 02/22/2004 05:40 AM Mark Jones wrote:
> My application allows a user to make various different types of
> bookings for a (fictional!!!) hospital and logs them in a database.
> Each type of booking has a set of common properties but also different
> ones depending on the type of booking being made.
>
> I have divided my classes into a BookingAction and BookingActionForm
> superclass and subclasses (such as AmbulanceBookingAction and
> AmbulanceBookingActionForm) because I anticipate creating other
> subtypes of BookingAction that use the same properties in the
> BookingAction class but not in the AmbulanceBookingAction subclass.
> This initially seemed to me to be in keeping with programming for code
> re-use and extensibility.
I have just one Action class for the whole app that all my Action
subclasses inherit. It does all the common processing that I need. It is
now after 2 years on the project fairly complex but it is really all
common functionality.
I can't see any need in my situation for having a different Action
superclass for each module.
>
> My problem with this is, if a user submits a form which posts its data
> via the ActionServlet to the AmbulanceBookingAction subclass, how
> would I ensure the BookingAction class did its stuff? Would it be
> better / easier to use separate, non-derived (from my superclasses)
> Actions and ActionForms to handle each type of booking and not
> subclass BookingAction and BookingActionForm (even though I would be
> repeating the some of the same properties common to each different
> type of booking)?
>
You make sure they do their stuff because they have the perform() or
execute() method, and they call the actual AmbulanceBookingAction for
example.
> I am concerned, though, not to lose points for not reusing code. It
> just seems to me, though, that trying to divvy the handling of the
> form data via inheritance is too complicated and / or unnecessary.
>
I once had a ActionForm superclass with getter / setter methods for
frequently occuring fields - but dropped it because the advantage was
trivial. And I started using DynaActionForms.
Adam
--
struts 1.1 + tomcat 5.0.16 + java 1.4.2
Linux 2.4.20 Debian
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Re: [Newbie] Is it worth subclassing your own Action and ActionForm
classes to attain code re-use?
Posted by Adam Hardy <ah...@cyberspaceroad.com>.
On 02/22/2004 05:40 AM Mark Jones wrote:
> My application allows a user to make various different types of bookings for
> a (fictional!!!) hospital and logs them in a database. Each type of booking
> has a set of common properties but also different ones depending on the type
> of booking being made.
>
> I have divided my classes into a BookingAction and BookingActionForm
> superclass and subclasses (such as AmbulanceBookingAction and
> AmbulanceBookingActionForm) because I anticipate creating other subtypes of
> BookingAction that use the same properties in the BookingAction class but
> not in the AmbulanceBookingAction subclass. This initially seemed to me to
> be in keeping with programming for code re-use and extensibility.
I have just one Action class for the whole app that all my Action
subclasses inherit. It does all the common processing that I need. It is
now after 2 years on the project fairly complex but it is really all
common functionality.
I can't see any need in my situation for having a different Action
superclass for each module.
>
> My problem with this is, if a user submits a form which posts its data via
> the ActionServlet to the AmbulanceBookingAction subclass, how would I ensure
> the BookingAction class did its stuff? Would it be better / easier to use
> separate, non-derived (from my superclasses) Actions and ActionForms to
> handle each type of booking and not subclass BookingAction and
> BookingActionForm (even though I would be repeating the some of the same
> properties common to each different type of booking)?
>
You make sure they do their stuff because they have the perform() or
execute() method, and they call the actual AmbulanceBookingAction for
example.
> I am concerned, though, not to lose points for not reusing code. It just
> seems to me, though, that trying to divvy the handling of the form data via
> inheritance is too complicated and / or unnecessary.
>
I once had a ActionForm superclass with getter / setter methods for
frequently occuring fields - but dropped it because the advantage was
trivial. And I started using DynaActionForms.
Adam
--
struts 1.1 + tomcat 5.0.16 + java 1.4.2
Linux 2.4.20 Debian
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Re: [Newbie] Is it worth subclassing your own Action and ActionForm classes to attain code re-use?
Posted by Oswald Campesato <oc...@yahoo.com>.
Hello, Rick:
I'm joining this out-of-context, so apologies if it's been discussed.
Some time ago I extended ActionServlet in order to collect some
timing-related results and then generated an XML file to which I
applied an XSL stylesheet in order to generate an SVG-based
bar chart.
Then I was hit with a virus on my PC (long story), and lost the
code after reformatting my hard drive:( Anyway, it wasn't rocket
science, and when I have time I'll rewrite the code.....
Cordially,
Oswald
Rick Reumann <st...@reumann.net> wrote:
On Sat, 2004-02-21 at 23:40, Mark Jones wrote:
> In what circumstances might you want to subclass your own Action class and,
> if you did, how would you handle/inherit the form data? Would you just use
> different subclasses of your Action but just one ActionForm for each Action?
Did you look at all at the e-mail that I sent you, and Robert Taylor
sent, in reference to this same question on the other list you posted
to?
--
Rick
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Re: [Newbie] Is it worth subclassing your own Action and
ActionForm classes to attain code re-use?
Posted by Rick Reumann <st...@reumann.net>.
On Sat, 2004-02-21 at 23:40, Mark Jones wrote:
> In what circumstances might you want to subclass your own Action class and,
> if you did, how would you handle/inherit the form data? Would you just use
> different subclasses of your Action but just one ActionForm for each Action?
Did you look at all at the e-mail that I sent you, and Robert Taylor
sent, in reference to this same question on the other list you posted
to?
--
Rick
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Re: [Newbie] Is it worth subclassing your own Action and ActionForm classes to attain code re-use?
Posted by Raphaël di Cicco <ra...@atosorigin.com>.
I use an ActionBaseForm where I put mapped getters/setters for the
properties so every sub-Form can use it without coding anything.
----- Original Message -----
From: "Mark Jones" <te...@markjones.ukf.net>
To: "Struts User" <st...@jakarta.apache.org>
Sent: Sunday, February 22, 2004 5:40 AM
Subject: [Newbie] Is it worth subclassing your own Action and ActionForm
classes to attain code re-use?
> My application allows a user to make various different types of bookings
for
> a (fictional!!!) hospital and logs them in a database. Each type of
booking
> has a set of common properties but also different ones depending on the
type
> of booking being made.
>
> I have divided my classes into a BookingAction and BookingActionForm
> superclass and subclasses (such as AmbulanceBookingAction and
> AmbulanceBookingActionForm) because I anticipate creating other subtypes
of
> BookingAction that use the same properties in the BookingAction class but
> not in the AmbulanceBookingAction subclass. This initially seemed to me to
> be in keeping with programming for code re-use and extensibility.
>
> My problem with this is, if a user submits a form which posts its data via
> the ActionServlet to the AmbulanceBookingAction subclass, how would I
ensure
> the BookingAction class did its stuff? Would it be better / easier to use
> separate, non-derived (from my superclasses) Actions and ActionForms to
> handle each type of booking and not subclass BookingAction and
> BookingActionForm (even though I would be repeating the some of the same
> properties common to each different type of booking)?
>
> I am concerned, though, not to lose points for not reusing code. It just
> seems to me, though, that trying to divvy the handling of the form data
via
> inheritance is too complicated and / or unnecessary.
>
> In what circumstances might you want to subclass your own Action class
and,
> if you did, how would you handle/inherit the form data? Would you just use
> different subclasses of your Action but just one ActionForm for each
Action?
>
> What is the best way for me to implement this problem? (Or have I answered
> my own question?! ;0) )
>
> Thanks for indulging me!
>
> Mark
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: struts-user-help@jakarta.apache.org
---------------------------------------------------------------------
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