package xml;
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 XPathTest 
{
	public static void main(String[] args) throws Exception 
	{
		//Build DOM
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		factory.setNamespaceAware(true); // never forget this!
		DocumentBuilder builder = factory.newDocumentBuilder();
		Document doc = builder.parse("inventory.xml");
		//Create XPath
		XPathFactory xpathfactory = XPathFactory.newInstance();
		XPath xpath = xpathfactory.newXPath();
		System.out.println("n//1) Get book titles written after 2001");
		// 1) Get book titles written after 2001
		XPathExpression expr = xpath.compile("//book[@year>2001]/title/text()");
		Object result = expr.evaluate(doc, XPathConstants.NODESET);
		NodeList nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}
		System.out.println("n//2) Get book titles written before 2001");
		// 2) Get book titles written before 2001
		expr = xpath.compile("//book[@year<2001]/title/text()");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}
		System.out.println("n//3) Get book titles cheaper than 8 dollars");
		// 3) Get book titles cheaper than 8 dollars
		expr = xpath.compile("//book[price<8]/title/text()");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}
		System.out.println("n//4) Get book titles costlier than 8 dollars");
		// 4) Get book titles costlier than 8 dollars
		expr = xpath.compile("//book[price>8]/title/text()");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}
		System.out.println("n//5) Get book titles added in first node");
		// 5) Get book titles added in first node
		expr = xpath.compile("//book[1]/title/text()");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}
		System.out.println("n//6) Get book title added in last node");
		// 6) Get book title added in last node
		expr = xpath.compile("//book[last()]/title/text()");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}
		System.out.println("n//7) Get all writers");
		// 7) Get all writers
		expr = xpath.compile("//book/author/text()");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}
		System.out.println("n//8) Count all books titles ");
		// 8) Count all books titles
		expr = xpath.compile("count(//book/title)");
		result = expr.evaluate(doc, XPathConstants.NUMBER);
		Double count = (Double) result;
		System.out.println(count.intValue());
		System.out.println("n//9) Get book titles with writer name start with Neal");
		// 9) Get book titles with writer name start with Neal
		expr = xpath.compile("//book[starts-with(author,'Neal')]");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i)
								.getChildNodes()
								.item(1)				//node <title> is on first index
								.getTextContent());
		}
		System.out.println("n//10) Get book titles with writer name containing Niven");
		// 10) Get book titles with writer name containing Niven
		expr = xpath.compile("//book[contains(author,'Niven')]");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i)
								.getChildNodes()
								.item(1)				//node <title> is on first index
								.getTextContent());
		}
		System.out.println("//11) Get book titles written by Neal Stephenson");
		// 11) Get book titles written by Neal Stephenson
		expr = xpath.compile("//book[author='Neal Stephenson']/title/text()");
		result = expr.evaluate(doc, XPathConstants.NODESET);
		nodes = (NodeList) result;
		for (int i = 0; i < nodes.getLength(); i++) {
			System.out.println(nodes.item(i).getNodeValue());
		}

		System.out.println("n//12) Get count of book titles written by Neal Stephenson");
		// 12) Get count of book titles written by Neal Stephenson
		expr = xpath.compile("count(//book[author='Neal Stephenson'])");
		result = expr.evaluate(doc, XPathConstants.NUMBER);
		count = (Double) result;
		System.out.println(count.intValue());
		System.out.println("n//13) Reading comment node ");
		// 13) Reading comment node
		expr = xpath.compile("//inventory/comment()");
		result = expr.evaluate(doc, XPathConstants.STRING);
		String comment = (String) result;
		System.out.println(comment);
	}
}