Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

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 org.w3c.dom.Document;
import org.w3c.dom.NodeList;

public class Main {
    public static void main(String[] args) throws Exception {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true);
        DocumentBuilder builder;
        Document doc = null;
        builder = factory.newDocumentBuilder();
        doc = builder.parse("employees.xml");
        // Create XPathFactory object
        XPathFactory xpathFactory = XPathFactory.newInstance();
        // Create XPath object
        XPath xpath = xpathFactory.newXPath();
        String name = getEmployeeNameById(doc, xpath, 4);
        System.out.println("Employee Name with ID 4: " + name);

        List<String> names = getEmployeeNameWithAge(doc, xpath, 30);
        System.out.println("Employees with 'age>30' are:" + Arrays.toString(names.toArray()));

        List<String> femaleEmps = getFemaleEmployeesName(doc, xpath);
        System.out.println("Female Employees names are:" + Arrays.toString(femaleEmps.toArray()));
    }

    private static List<String> getFemaleEmployeesName(Document doc, XPath xpath) throws Exception {
        List<String> list = new ArrayList<>();
        XPathExpression expr = xpath.compile("/Employees/Employee[gender='Female']/name/text()");
        // evaluate expression result on XML document
        NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);
        for (int i = 0; i < nodes.getLength(); i++)
            list.add(nodes.item(i).getNodeValue());
        return list;
    }

    private static List<String> getEmployeeNameWithAge(Document doc, XPath xpath, int age) throws Exception {
        List<String> list = new ArrayList<>();
        XPathExpression expr = xpath.compile("/Employees/Employee[age>" + age + "]/name/text()");
        NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);
        for (int i = 0; i < nodes.getLength(); i++)
            list.add(nodes.item(i).getNodeValue());
        return list;
    }

    private static String getEmployeeNameById(Document doc, XPath xpath, int id) throws Exception {
        String name = null;
        XPathExpression expr = xpath.compile("/Employees/Employee[@id='" + id + "']/name/text()");
        name = (String) expr.evaluate(doc, XPathConstants.STRING);
        return name;
    }

}