[OpenLayers-Dev] [OpenLayers-Trac] [OpenLayers] #1324: OpenLayers.Feature.Vector.clone() must clone the fid property.

Christopher Schmidt crschmidt at metacarta.com
Mon Feb 11 21:52:50 EST 2008

On Tue, Feb 12, 2008 at 09:54:28AM +1100, Roald de Wit wrote:
> Hi,
> On Mon, 2008-02-11 at 09:17 -0500, Christopher Schmidt wrote:
> > On Thu, Feb 07, 2008 at 03:18:55PM -0000, OpenLayers wrote:
> > > #1324: OpenLayers.Feature.Vector.clone() must clone the fid property.
> > 
> > Anyone have thoughts on this? I'm not sure if we should be cloning this,
> > since it feels to me like a clone is a different object, and fids should
> > be unique...
> If the requirement is that an object must always have a unique fid, then
> not cloning the fid is also insufficient.
> You'd have to create a new unique fid. The simplest way would be copying
> the original fid and adding a random number, like: 
> newObject.fid = oldObject.fid + "_" + Math.round(Math.random() * 1000));

Actually, There's an OpenLayers.Util.createUniqID(), which is
guartenteed to be unique. (I might have spelled it wrong.) IT uses a
monotonically increasing value.

That's not really here nor there though. Your point is correct: if a
*unique* FID is required, then it should be set to something uniquely
generated (presumably at the application level). However, what I
actually meant was "a unique or null FID": 'null' usually means 'use the
remote server to populate one for me', instead of using the value as a
FID. This is the behavior I think makes the most sense: for most
applications, when you clone a feature, you want to keep a null FID
until you serialize and post to a server, and *then* do the logic to
create one and assign it on the client.

With that in mind, i think not cloning the FID is a good idea.

Christopher Schmidt

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