Lehekülje ITI0011RUS:task 10 Sample lähteteksti vaatamine

Обратно на [[ITI0011RUS|страницу предмета]].

<source lang="java">
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.ArrayList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import cs.ttu.ee.BookShopApi;
import cs.ttu.ee.BookShopApiException;
import cs.ttu.ee.SimpleBookShop;
 
 
/**
 * BookShop class.
 * Simplified implementation of BookShop 
 * Does filtering and basic queries.
 */
public class BookShop extends SimpleBookShop {
 
	/**
	 * Instance of BookShopApi, used to access
	 * Google Books
	 */
	private BookShopApi bookShopApi;
 
	/**
	 * Last api query result.
	 */
	private String lastResponse = "";
 
	public BookShop(BookShopApi _bookShopApi) {
		bookShopApi = _bookShopApi;
	}
 
	/**
	 * Make api query. 
	 * Uses BookStoreApi functionality to get XML response from Google Books
	 * Every time this function is called, latest XML state is saved.
	 * If previous query failed lastResponse equals to empty string.
	 * Otherwise lastResult is 
	 * @param search title of book 
	 */
	public void query(String searchString) {
		try {
			lastResponse = bookShopApi.getBookByTitle(searchString);
		} catch (BookShopApiException e) {
			lastResponse = "";
		}
	}
	
	private NodeList getXPathData(String xPathStr) {
		if(lastResponse.isEmpty()) {
			return null;
		}
		try {
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = dbf.newDocumentBuilder();
			Document xmlDocument = builder.parse(
					new ByteArrayInputStream(lastResponse.getBytes()));
			XPathFactory xpf = XPathFactory.newInstance();
			XPath xPath = xpf.newXPath();
			XPathExpression expr = xPath.compile(xPathStr);
			return (NodeList) expr.evaluate(xmlDocument, XPathConstants.NODESET);
		} catch (
				ParserConfigurationException | 
				SAXException | 
				IOException | 
				XPathExpressionException e) {
			return null;
		}
		
	}
 
	/**
	 * Find total items matched by searchString.
	 * Api uses paging, not all results are 
	 * displayed under result, however, total 
	 * results is displayed inside <totalItems> element
	 * 
	 * If last query was unsuccessful, 0 is returned.
	 * 
	 * @return Total items matched by query.
	 */
	public int getTotalRecordsInResponse() {

		NodeList records = getXPathData("/result/totalItems");
		
		for(int i=0; i<records.getLength(); ++i) {
			Node node = records.item(i);
			String v = node.getTextContent();
			return Integer.parseInt(v);
		}
		
		return 0;
	}
 
 
	/**
	 * Finds all possbile book titles.
	 * Duplicates may occur.
	 * 
	 * Title can be found inside <title> tag.
	 * If last query was unsuccessful, empty ArrayList is returned.
	 * 
	 * @return All possible book names matched by searchString
	 */
	public ArrayList<String> getPossibleBookTitles() {
		
		ArrayList<String> bookTitles = new ArrayList<String>();
		
		NodeList records = getXPathData("//title");
		
		for(int i=0; i<records.getLength(); ++i) {
			Node title = records.item(i);
			bookTitles.add(title.getTextContent());
		}
		
		return bookTitles;
	}
 
	/**
	 * Finds all authors found in last response.
	 * Does not include duplicate authors.
	 * If last query was unsuccessful, empty ArrayList is returned.
	 * 
	 * Author can be found inside <authors> element. (Notice non plural form)
	 * NB! Multiple <authors> element may occur.
	 * 
	 * @return List of authors found in last response
	 */
	public ArrayList<String> getPossibleAuthors() {
		// TODO: implement
		return null;
	}
 
	/**
	 * Finds book with the most number of pages
	 * 
	 * Page count can be found inside  <pageCount> element
	 * @return Title of book.
	 */
	public String getBookWithMostPagesTitle() {
		// TODO: implement
		return null;
	}
 
	/**
	 * Finds all book titles where pageCount < n
	 * 
	 * Page count can be found inside  <pageCount> element
	 * @param n maximum amount of pages
	 * @return list of books with less than n pages
	 */
	public ArrayList<String> getBookWithLessThanNPagesTitles(int n) {
		// TODO: implement
		return null;
	}


}
</source>