XPath and XML Schema

[mig]

I have XML Schema (or DTD) file and XPath String on the input and need piece
of Java code (probably using some free API) which will give me the answer to
the following question:
"Can we build an XML file compliant to the given XML Schema (or DTD) in
which given XPath select at least one element/attribute?".
I need at least functionality for the simple XPaths, like: /AAA/BBB/@CCC

thanks, mig