Re[2]: [cgmo-webcgm] WebCGMNodeList

[Benoit Bezaire <benoit@itedo.com>]

Hi Stuart,

GSA> The proposal looks good to me, but I would like to see something about
GSA> the WebCGMNode.attributes retaining the read/write ability.
You will still be able to modify the attribute values, but you will
not be able to add or remove attributes from a WebCGMNodeList
interface. Okay? But will be able to do so using the
WebCGMAppStructure interface.

GSA>  Also, should it be possible to add an attribute at runtime?
Yes.

GSA> For example: use the script to add a screentip?
var a = cgmPic.createWebCGMStringList();
a.appendItem("A runtime screentip");
someobject.setAppStructureAttrList( "screentip", a );

or

var a = cgmPic.createWebCGMStringList();
a.appendItem("A runtime screentip");
var l = someobject.attributes;
var i = l.getItem( 2 /* assuming 2 represents the screentip */ );
i.value = a;

I prefer the first approach, it is cleaner.

-- 
 Benoit   mailto:benoit@itedo.com

 
GSA> --
GSA> Stuart Galt
GSA> SGML Resource Group
GSA> stuart.a.galt@boeing.com
GSA> (206) 544-9925 

GSA> -----Original Message-----
GSA> From: Benoit Bezaire [mailto:benoit@itedo.com] 
GSA> Sent: Thursday, February 10, 2005 1:33 PM
GSA> To: CGM Open WebCGM TC
GSA> Subject: [cgmo-webcgm] WebCGMNodeList


GSA> Hi guys,

GSA> I'm unclear about something... that is, how are users going to use
GSA> WebCGMNodeList!? 

GSA> We have the following methods which return WebCGMNodeList:
GSA>   WebCGMNodeList WebCGMNode.childNodes;
GSA>   WebCGMNodeList WebCGMNode.attributes;
GSA>   WebCGMNodeList WebCGMNode.getElementsByTagNameNS()
GSA>   WebCGMNodeList WebCGMPicture.getAppsStructureByName()
GSA>   WebCGMNodeList WebCGMPicture.createWebCGMNodeList()

GSA> And the following which requires one as input:
GSA>                  WebCGMPicture.hightlight(in WebCGMNodeList)

GSA> The WebCGMNodeList interface is as follows:
GSA> interface WebCGMNodeList {
GSA>   readonly   attribute unsigned long count;
GSA>   WebCGMNode           item(in unsigned long index);
GSA>   WebCGMNode           removeItem ( in unsigned long index )
GSA>                                          raises( WebCGMException );
GSA>   WebCGMNode           appendItem ( in WebCGMNode newItem )
GSA>                                          raises( WebCGMException );
GSA>   void                 clear()
GSA>                                          raises( WebCGMException ); };

GSA> My concerns are related to a node list of APS nodes and a node list of
GSA> Attr nodes. It is pretty clear that 'count' and 'item' have value; they
GSA> are required to walk through a list of nodes regardless if they are APS
GSA> or Attr.

GSA> In a previous email, I said that there are technical reasons why 'clear'
GSA> shouldn't be present. So that leaves 'removeItem' and 'appendItem' as
GSA> questionable... Let's start with 'appendItem', it is needed for adding
GSA> WebCGMNodes to a list of objects to be highlighted. But what happens if
GSA> someone does:

GSA> WebCGMNode.childNodes.appendItem() // this adds a new child

GSA> I thought we wanted to forbid the 'addition' and 'deletion' of APS in
GSA> the DOM. If that is true, I don't see a use case for 'removeItem',
GSA> except maybe to remove an item from a node list which shouldn't be
GSA> highlighted.

GSA> 'removeItem' and 'appendItem' on Attr node list also have some issues.
GSA> 'removeItem' could be seen as an equivalent to removeAppStructureAttr,
GSA> and 'appendItem' as setAppStructureAttrList. The problem is that we
GSA> don't have a createAttrNode method to feed into appendItem. Should we
GSA> add such a method?

GSA> I'm not sure if people are following me, I may not be very clear. But
GSA> here's my proposal.

GSA> Proposal:
GSA> All methods returning a WebCGMNodeList, with the exception of
GSA> createWebCGMNodeList, must return 'readonly' node lists. With this
GSA> approach 'appendItem' and 'removeItem' can remain on the interface and
GSA> will only work for node lists aimed at being used with the highlight()
GSA> method.

GSA> Thoughts?