Joe,
Your timing on this was impeccable! I just spent the past hour
wrestling with ObjectCopy (both Manish's and the mx.utils one that
doesn't work).
So here is Manish's ObjectCopy with Joe's hack to preserve type:
public static function copy(source):Object
{
var cl:Number = copyCache.length;
for (var i:Number = 0; i < cl; i++)
{
var o = copyCache[i];
if (o.s == source)
return o.t;
}
copyDepthLevel++;
var newObj;
if (typeof(source.__constructor__) == "function")
{
// for AS2 classes
newObj = new source.__constructor__();
}
else if (typeof(source.constructor) == "function")
{
// for Arrays and Objects
newObj = new source.constructor();
}
else
{
// for goodness sake, instantiate *something*!
newObj = new Object();
}
copyCache.push({s: source, t: newObj});
for (var p in source)
{
var v = source[p];
newObj[p] = typeof v == "object" ? copy(v) : v;
}
if (--copyDepthLevel == 0)
copyCache = [];
return newObj;
}
Notice that the method signature changed slightly. This was to avoid
this error:
Error: A function call on a non-function was attempted.
due to:
newObj = new source.constructor();
I have tested this code in my app and it's working great! Thanks Joe
and Manish!
-James
On Wed, 2005-06-22 at 11:18 -0400, Joe Berkovitz wrote:
> A couple of big caveats here.
>
> 1. mx.utils.ObjectCopy is broken. (At least, in the Flex 1.5
> distribution.) It does not correctly preserve the class of an object
> when that class is a subclass of some superclass. Instead, the copied
> object will appear to have the type of the superclass.
>
> I note that ObjectCopy appears to only be used in net debugging and
> nowhere else. So this bug isn't exposed via any documented Flex APIs.
>
> Moral: beware of undocumented internal Flash classes, however convenient
> they might look.
>
> 2. Even if ObjectCopy worked, you cannot conveniently meld Manish's
> cached-array approach with it, because ObjectCopy will do the wrong
> thing with cycles (it locks up) and multiply referenced objects (it
> duplicates instances).
>
> So.... what to do?
>
> As empirically determined through testing, one correct approach in Flex
> 1.5 to instantiating an object that preserves the type of an existing
> one is as follows:
>
> var newObj;
> if (typeof(obj.__constructor__) == "function")
> {
> // for AS2 classes
> newObj = new obj.__constructor__();
> }
> else if (typeof(obj.constructor) == "function")
> {
> // for Arrays and Objects
> newObj = new obj.constructor();
> }
> else
> {
> // for goodness sake, instantiate *something*!
> newObj = new Object();
> }
>
> I've exhaustively tested this and it works correctly for AS2 classes,
> for Arrays, and for untyped Objects. You can merge it with Manish's
> code (which I haven't tested, but looks good) to produce a working,
> accurate deep copy.
>
> .. . . . . j
>
>
> Abdul Qabiz wrote:
> > http://manish.revise.org/2005/04/deepcopying-actionscript-objects.html
> >
> > http://www.darronschall.com/weblog/archives/000148.cfm
> >
> >
> > -abdul
> >
> >
> > -----Original Message-----
> > From: [email protected] [mailto:[EMAIL PROTECTED] On
> > Behalf Of Pradeep Chaudhary
> > Sent: Wednesday, June 22, 2005 7:33 PM
> > To: [email protected]
> > Subject: [flexcoders] How to create copy of a object
> >
> > I want to create a copy for my custom object before it is modified so
> > that i can rollback my changes on any error condition. Do we have any
> > inbuilt methods or any alternative solution for creating a copy of
> > object so that changes made to original object is not reflected copied
> > object.
> >
> > Pradeep
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
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