Anyone? I'm sure this sort of thing comes up pretty frequently--I'd be
curious to know how other Flex users tackle it.
-Maciek
-Original Message-
From: Maciek Sakrejda msakre...@truviso.com
Reply-To: flexcoders@yahoogroups.com
To: flexcoders flexcoders@yahoogroups.com
Subject: [flexcoders] design question: editing / saving complex value
objects
Date: Wed, 18 Feb 2009 10:35:04 -0800
Suppose I have a class Calendar that mirrors a server-side class (we're
not really working with Calendars, but I think this is a reasonably good
and simple analogy):
class Calendar {
public var appointments:ArrayCollection;
/* other stuff */
}
Then I want users to be able to edit and save the Calendar: I have a
CalendarEditor. Editing a Calendar is moderately complicated (e.g.,
adding, removing, or editing Appointments), so I want explicit
save/cancel steps.
When editing something really simple, this is not really a problem--when
the user saves, I propagate the view state to the object; when she hits
cancel, I don't do anything.
However, the Calendar determines what combination of Appointments is
valid (they can't overlap), and the Calendar is the dataProvider of the
CalendarEditor, so I can't fully validate a combination of Appointments
without adding them to the Calendar. This means I actually need to add
the appointments to the Calendar before it is saved so that they can be
(a) validated in combination and (b) used to update the view while the
edit is in progress. This makes save/cancel steps trickier: do I
(1) Clone the Calendar (and therefore have it provide a clone() method)
when assigned in the dataProvider, modify the clone, and assign the
dataProvider reference when the user hits save.
(2) Clone the Calendar as above, but have the Editor modify the
original, and restore the clone in case the user cancels.
(3) Something more clever?
The problem with (1) is that cloning may be somewhat complicated, and it
feels ugly to have the Editor update the dataProvider reference
(instead of modifying the actual object that was set as the data
provider). (2) hits the same issue. Perhaps the solution is to maintain
a private clone, and copy back the state on save? Or is the right answer
here that the model should not expect that the editor will update the
object it set as the dataProvider, but should instead expect an update
through a mechanism like a Mate map?
Any thoughts? (Please keep in mind that my experience with MVC
frameworks is unfortunately minimal, though I'm looking into Mate right
now).
Thanks,
Maciek
