XMLShelfWriter.java

package ${package};

import java.io.File;

import javax.xml.parsers.*;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

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

public final class XMLShelfWriter implements ShelfWriter {
    private String filename = "bookshelf.xml";

    public String getFilename() {
        return filename;
    }

    public void setFilename(final String file) {
        this.filename = file;
    }

    @Override
    public Bookshelf load() {
        return null;
    }

    @Override
    public void write(final Bookshelf shelf) {
        DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder;
        try {
            builder = builderFactory.newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            throw new RuntimeException(e);
        }
        Document document = builder.newDocument();
        Element root = document.createElement("shelf");

        for (int i = 0; i < shelf.bookCount(); ++i) {
            Element book = document.createElement("book");
            book.setAttribute("id", Integer.toString(i));

            Element e = document.createElement("author");
            e.appendChild(document.createTextNode(shelf.get(i).getAuthor()));
            book.appendChild(e);

            e = document.createElement("title");
            e.appendChild(document.createTextNode(shelf.get(i).getTitle().toString()));
            book.appendChild(e);

            e = document.createElement("isbn");
            e.appendChild(document.createTextNode(shelf.get(i).getIsbn().stripped()));
            book.appendChild(e);

            e = document.createElement("price");
            e.appendChild(document.createTextNode(Float.toString(shelf.get(i).getPrice())));
            book.appendChild(e);

            root.appendChild(book);
        }

        document.appendChild(root);

        DOMSource source = new DOMSource(document);
        StreamResult output = new StreamResult(new File(filename));

        Transformer transformer;
        try {
            transformer = TransformerFactory.newInstance().newTransformer();
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            transformer.setOutputProperty(OutputKeys.ENCODING, "utf-8");
            transformer.transform(source, output);
        } catch (TransformerConfigurationException e) {
            throw new RuntimeException(e);
        } catch (TransformerFactoryConfigurationError e) {
            throw new RuntimeException(e);
        } catch (TransformerException e) {
            throw new RuntimeException(e);
        }
    }
}