package com.darwinsys.xml;
import java.io.Console;
import java.io.FileInputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
/**
* Simple interactive use of XPath, which is supported in JAXP (in
* JavaSE package javax.xml.xpath) since JDK 1.5.
*/
public class XPathRunner {
private static String fileName;
private static String expr;
private static Document document;
public static void main(String[] args) throws Exception {
switch (args.length) {
case 0:
System.err.println("Usage: XPathRunner file [xpath-expr]\n");
return;
case 2:
expr = args[1];
/*FALLTHROUGH*/
case 1:
fileName = args[0];
break;
}
DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
document = parser.parse(new FileInputStream(fileName));
boolean done = false;
if (expr == null) do {
expr = promptForPathExpr();
System.out.println(eval(expr));
} while (!done);
else {
System.out.println(eval(expr));
}
}
private static String eval(String expr) throws XPathExpressionException {
/** evaluate the XPath expression against the Document */
XPath xpath = XPathFactory.newInstance().newXPath();
String secNum = (String) xpath.evaluate(expr, document, XPathConstants.STRING);
return secNum;
}
private static String promptForPathExpr() {
Console c = System.console();
if (c == null) {
throw new IllegalStateException("This app needs a 'controlling terminal' to prompt; use with filename and expr arguments");
}
return c.readLine("Enter XPath prompt for %s", fileName);
}
}