SV:Querying an XML File

[Gr�ndal Daniel]

Hi!

That's a thing for Xalan. I do it that way. First I use Xerces (DOM) to do some
stuff and then I wrap the DOM-tree and pass it to Xalan.

More or less like this:

  try
   {
      XMLPlatformUtils::Initialize();
   }
   catch (const XMLException& toCatch)
   {
      char* message = XMLString::transcode(toCatch.getMessage());
         // throw exception with message
   }
   impl =
DOMImplementationRegistry::getDOMImplementation(XMLString::transcode("LS"));
   parser = ((DOMImplementationLS*)
impl)->createDOMBuilder(DOMImplementationLS::MODE_SYNCHRONOUS, 0);
   doc = parser->parseURI("inputfile.xml");

  // do stuff with doc


  // use Xalan to evaluate xPath's
   XPathEvaluator::initialize();
   XPathEvaluator    eval;

   XercesDOMSupport domsupport;
   XercesParserLiaison parserLiaison;        // for communication

   // xml-file is already parsed. don't want to do that again
   const XercesDOMWrapperParsedSource parsedSource(
                                   doc,
                                   parserLiaison,
                                   domsupport);


  // count nodes as example
   XalanDocument* xalanDoc = parsedSource.getDocument();

  // get root node
   XalanElement* rootElement= xalanDoc->getDocumentElement();

  // select all nodes that matches xPath
  // read xPath from user or whatever
   NodeRefList nodelist = eval.selectNodeList (domsupport, (XalanNode*)
rootElement, XalanDOMString(xpath.c_str()).c_str());
   int elements = nodelist.getLength();

  // and so on


Don't know if this is the fastest way do to stuff. It is just one way to do it..
.
You can also manipulate trees (I think?) with Xalan and write them back using
Xerces

//daniel


[EMAIL PROTECTED]  (2003-07-21  03:34):
>Hi folks,
>
>not sure if I'm barking up the wrong tree here, but is there an API to
>extract nodes from a file (or DOM) using XPath strings? This would be a
>really powerful feature for manipulating trees.
>
>==============================
>Oliver White
>Software Engineer
>Product Development
>Westinghouse Signals Australia
>==============================
>
>
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