I have been trying out a new solution to this "age-old" conundrum. I
have a UserContainer implements Map object in the Session object. The
UserContainer object implements the Map as indicated in my
http://wiki.apache.org/struts/StrutsCatalogInstrumentableForms, except
that the UserContainer does not extend ActionForm. I populate and
de-poplulate the UserContainer in the model for each request as
indicated in a workflow. This is particularly easy to employ with the
BeanMap implementation that can be instrumented.
Michael
Leandro Melo wrote:
Rick,
i agree with you, i also use BeanUtils to populate my
forms.
But, this doesn't go far way from having your
ActionForms dependent on your TOs (or CustomTOs,
doesn' t matter).
As Sebastian said, i've heard a lot that TOs should
mirror or shouldn't be coupled to your ActionForms,
but i really don't how it's possible to build a very
modular architecture without this coupling.
--- Rick Reumann <[EMAIL PROTECTED]> escreveu:
Sebastian Ho wrote:
Say I retrieve a TO from database and convert it
into a actionForm for
display. In this case I have 4 fields for my
actionForm but 10 in my TO.
(6 are not needed for display). A user updates the
4 fields and the
action convert those into TO. In this case, the
other 6 fields will be
reset to null(or empty) in my database!
To prevent this, I actually need to use hidden
fields in my JSP or some
other ugly solutions in my Action class. They are
still dependent on
each others afterall.
You can handle this several ways...
For example, one solution is you create a
TransferObject that refers to
only the fields you care about - in this case the 4
fields you
mentioned. So your call to the business layer would
return that
TransferObject and you could then convert that
easily to your form
(using BeanUtils). Then going back the other way
your business layer
would take as an arguemnt the same type of
TransferObject.
I actually don't prefer the above, though, because
say later on you
decide you want to add another field to your form
now your backend has
to worry about handling a new object with different
fields.
I think the best solution is to simply make another
call to get back the
initial TO from the db, then simply use BeanUtils to
populate that TO
with the form fields. It will only set the fields in
which it has the
same names for so your other data will be fine.
So it looks like...
TransferObject to =
BackendEnd.getMyTransferObject(..);
MyForm myForm = (MyForm)form;
BeanUtils.copyProperties( to, myForm);
BackEnd.doUpdate( to );
Pretty simple I think. Just make sure your
ActionForm doesn't contain
properties that you don't care about editing
otherwise it will
over-write the TO properties. If the JSP form is
going to be very
dyanmic, as in it will sometimes have some
properties and sometimes have
others, then you will have to use more complex
'tricks' such as using
hidden variables.. or I'd just prefer to manually
set the TO fields in
the Action.
--
Rick
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