import javax.xml.xpath.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;

public class XPathEvaluator {
    public static void main(String[] args)
	throws ParserConfigurationException, XPathExpressionException,
	       org.xml.sax.SAXException, java.io.IOException
    {
	String documentName = args[0];
	String expression = args[1];

	// Parse the document to a DOM tree
	// XPath can also be used with a SAX InputSource
	DocumentBuilder parser =
	    DocumentBuilderFactory.newInstance().newDocumentBuilder();
	Document doc = parser.parse(new java.io.File(documentName));
	
	// Get an XPath object to evaluate the expression
	XPath xpath = XPathFactory.newInstance().newXPath();

	System.out.println(xpath.evaluate(expression, doc));

	// Or evaluate the expression to obtain a DOM NodeList of all matching
	// nodes.  Then loop through each of the resulting nodes
	NodeList nodes = (NodeList)xpath.evaluate(expression, doc,
						  XPathConstants.NODESET);
	for(int i = 0, n = nodes.getLength(); i < n; i++) {
	    Node node = nodes.item(i);
	    System.out.println(node);
	}
    }
}