Re: Xalan/Xerces/XPath

[David N Bertoni/Cambridge/IBM]

You should search the archives of this list and the Xalan-C developer list
-- there have been numerous posts on this subject.  In general, as long as
you do things correctly, you should not have any problems.  The biggest
issue is mapping nodes from Xalan back to the original Xerces document.  If
your XPath expressions all evaluate to boolean, then you won't need to
worry about this.  Another issue is how large your documents are and what
sort of performance you're expecting.  In particular, since you don't need
to map nodes, you should build the entire bridge at once.  See:

http://xml.apache.org/xalan-c/apidocs/class_xercesparserliaison.html#a27

If you're not sharing document instances amongst threads, save yourself
some cycles, and pass false for the "threadSafe" parameter.

Dave



                                                                                       
                                                           
                      "Anthony                                                         
                                                           
                      Zawacki"                 To:      [EMAIL PROTECTED]       
                                                           
                      <[EMAIL PROTECTED]         cc:      (bcc: David N 
Bertoni/Cambridge/IBM)                                                      
                      om>                      Subject: Xalan/Xerces/XPath             
                                                           
                                                                                       
                                                           
                      03/18/2002 05:52                                                 
                                                           
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Hello,

I am upgrading from Xalan 1.1 to Xalan 1.3 in a project that I am working
on, and have run across the following issues:

Due to the way that DOM objects are manipulated, I need to use Xerces to
control the DOM objects before a transformation.

I am now using a XalanTransformer with compiled stylesheets to do the
transformations.

In the past, I read XPath expressions from a configuration file (which also
contains unrelated arbitrary transformations,) created a basic stylesheet
for them, and then compiled them.  Later, I would do the transformation,
and check to see if the return value was true or false.  Now I think I want
to use the XPathEvaluator (which appears to be exactly what I needed.)

Do I face any unforseen issues by using a XercesParserLiaison to create a
XalanDocument from my Xerces document, and then passing that XalanDocument
into the



 XObjectPtr XPathEvaluator::evaluate (

                                  DOMSupport & domSupport,


                                  XalanNode * contextNode,


                                  const XPath & xpath,


                                  const XalanElement * namespaceNode = 0�)





method?

My expectations would be that the XObject would be an XBoolean output.

Thanks,

Anthony