MainClass.java Source code

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Here is the source code for MainClass.java

Source

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Hashtable;

import javax.xml.namespace.QName;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import javax.xml.xpath.XPathVariableResolver;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class MainClass {
    public static void main(String[] args) throws Exception {
        SimpleDateFormat xmlDateFormat = new SimpleDateFormat("MM.dd.yy");

        MapVariableResolver resolver = new MapVariableResolver();
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = dbf.newDocumentBuilder();
        Document document = builder.parse(new File("t.xml"));

        XPathFactory factory = XPathFactory.newInstance();
        XPath xPath = factory.newXPath();
        xPath.setXPathVariableResolver(resolver);
        XPathExpression expression = xPath.compile("/schedule/show[@date=$date]/guest");

        String formattedDate = xmlDateFormat.format(new Date(2006, 5, 14));
        resolver.addVariable(null, "date", formattedDate);
        Element guest = (Element) expression.evaluate(document, XPathConstants.NODE);

        System.out.println(guest.getElementsByTagName("name").item(0).getTextContent());
    }
}

class MapVariableResolver implements XPathVariableResolver {

    private Hashtable variables = new Hashtable();

    public void addVariable(String namespaceURI, String localName, Object value) {
        addVariable(new QName(namespaceURI, localName), value);
    }

    public void addVariable(QName name, Object value) {
        variables.put(name, value);
    }

    public Object resolveVariable(QName name) {
        Object retval = variables.get(name);
        return retval;
    }
}