XPath selections

[Tobias McNulty <tm...@datadesk.com>]

If I call selectSingleNode on a given root, with a expression such as 
"object[@id=1]", what actual nodes does Xalan search?  I am running 
Xerces to handle XML parsing and DOM.  My concern is this: since 
attributes are Nodes in Xerces, will Xalan test against _all_ the 
node children of 'object', including its elements, text nodes, etc., 
looking for the attribute 'id'?

Thanks,
Toby
-- 
Tobias McNulty
Data Description, Inc.
840 Hanshaw Road, Suite 9
Ithaca, NY 14850
Phone: (607) 257-1000
E-mail: tmcnulty@datadesk.com
Web: www.datadesk.com

Re: XPath selections

[Tobias McNulty <tm...@datadesk.com>]

>If I call selectSingleNode on a given root, with a expression such 
>as "object[@id=1]", what actual nodes does Xalan search?  I am 
>running Xerces to handle XML parsing and DOM.  My concern is this: 
>since attributes are Nodes in Xerces, will Xalan test against _all_ 
>the node children of 'object', including its elements, text nodes, 
>etc., looking for the attribute 'id'?
>
>Thanks,
>Toby

I did more tests; it appears that selectSingleNode does search the 
other direct children.  It also appears to search _all_ the children 
of the node, for example if I have:

<root>
	<object>
		<data>
			<data>
				<data>
					<r/>
					<r/>
				</data>
			</data>
		</data>
		<prop id="1"/>
	</object>
</root>

and I do a selectSingleNode with <root> as the context and the XPath 
expr "prop[@id=1]", Xalan appears to run through the data tree and 
grab the values of  the <r> elements.

Is this because the DOM to DTM code creates a full replica of the 
Xerces DOM in DTM format before running the XPath selection on the 
document?

Thanks,
Toby
-- 
Tobias McNulty
Data Description, Inc.
840 Hanshaw Road, Suite 9
Ithaca, NY 14850
Phone: (607) 257-1000
E-mail: tmcnulty@datadesk.com
Web: www.datadesk.com