Excellent design practices and I'm not really a hacker, I only play one for 
this current employer.

The incoming XML is truly trivial and the fault occurs before the XSLT 
transformer runs the XSLT, so either the code I have written is flawed (most 
likely) or it has stumbled over a real Xalan XPath bug.

No, we can't switch to pathan for schedule and feature reasons.

On Thursday 16 June 2005 12:10 pm, Axel Weiß wrote:
> Lonnie VanZandt wrote:
> > No, I can't share those because they are highly proprietary. But, they
> > are actually irrelevant to conceptual work to be done. Which I can
> > discuss.
> >
> > I have distributed servers which pass XML strings as their messages.
> > The servers are mostly stateless and transform an input XML into an
> > output XML based on XSLT-scripted "business logic".
> >
> > The transformer is humming along fine.
> >
> > However, occassionally, a server needs to peek into an incoming XML
> > request or an outgoing XML reply in order to do content-specific
> > processing above and beyond what the XSLT can do (such as determining
> > destinations and session management).
> >
> > So, rather than code up a mess of DOM traversal code, I need/want to
> > ask an XPathEvaluator to evaluate some "peeks" into the source and
> > output XML documents.
> >
> > Therefore, a string of XML arrives on a socket, I parse the XML into a
> > XalanDocument, I (try to) peek into the request with XPathEvaluator, I
> > get any state I need, I set XSLT stylesheet parameters, I let
> > XalanTransformer do its transformation, I (try to) peek into reply
> > with XPathEvaluator, I get any state I need, and I send off the reply
> > XML to the proper socket.
> >
> > I have two wishes:
> >
> > 1. That XPath::executeMore not return a null nodeset() or, at least,
> > that XPathEvaluator::selectNodeList not try to nodeset() on a
> > *XObjectPtr which isn't actually a NodeRefList.
> >
> > 2. To have the XalanTransformer use its parseSource method to parse
> > the input XML once for both the XPath query and then for the
> > transform() method (rather than constructing a separate XalanDocument
> > with the parserLiaison just for the XPath evaluator) and then use the
> > XalanTransformer to parse the reply XML so that the post-transform
> > XPath query can use that without having to construct a new
> > XalanDocument for the output string.
> >
> > Makes sense?
>
> That sounds all reasonable to me. However, when I develop some complex
> concepts (and the above is fairly complex ;), I usually try to break
> down some simple examples that show 1. the principles and 2. the core
> algorithms. I usually enforce this when I run into problems and want to
> communicate and discuss some non-obvious solutions.
>
> If I got you right, the problem is located in the (non-) ability of xalan
> to evaluate some XPath expression. Anything special with this
> expression? Can you possibly simplify the context where you encounter
> the problem, to a xml-file/xpath-expression pair that can reproduce the
> erroneous behaviour (and that is not top-secret;)?
>
> I have not very much experience with xpath-magics, just enough to be able
> to write the stylesheets I demand. I heard about that xerces has very
> little xpath support, xalan a bit more. But - did you already try
> pathan? Maybe it's worth a look...
>
> Cheers,
>                       Axel
>
> (You need not CC me, 'cause I'm subscribed here ;)


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