Help - newbie : variable evaluation within xpath expression evaluation 2003-01-22 - By Dhananjay Nene
Hello,
I am attempting to evaluate xpath on a dom and am currently using the
w3c api to do so. I am attempting perform xpath evaluation using apis
for the first time ... so my code may need some optimisation.
I wish to run almost similar xpath expressions repeatedly except for a
few changing values in the expression which I embed in the XPATH
expression string using $variable syntax. Subsequently I want to
continuously reevaluate the expression repeatedly for differing values
of $variable.
The current code look somewhat like following (shortened and cleaned up
for brevity)
public void foo(String xpath, File fileToOpen)
{
DocumentBuilderFactory docBuilderFactory =
DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
Document doc = docBuilder.parse(fileToOpen);
XPathEvaluator evaluator = new XPathEvaluatorImpl(doc);
XPathNSResolver resolver = evaluator.createNSResolver(doc);
XPathExpression = evaluator.createExpression(xpath,resolver);
XPathResult result = (XPathResult)expr.evaluate(
doc, XPathResult.UNORDERED_NODE_ITERATOR_TYPE, null);
Node resultNode = null;
while ((resultNode = result.iterateNext()) != null)
{ ... blah ... }
}
When I embed the $variable (e.g. the XPath looks like
"/Foo1/Foo2[Foo3=$variable]", I get the following exception
Variable not resolvable: variable at
org.apache.xpath.axes.PredicatedNodeTest.acceptNode(PredicatedNodeTest.java:449)
.....
I am certain the xpath engine expects me to supply the value for
variable, but I do not know how to do so. Can someone help me out ?
My feeling is that this objective may not be solved using the
javax.xml.transform + org.w3c apis, and I shall need to resort to
org.apache.xalan / org.apache.xpath apis. I shall welcome any
suggestions using that approach also.
Dhananjay
__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com
|
|
