XML to JTree with broken nodes: attributes should be leaves

XmlToJtree.java

/**
 * Uses code from Ibbtek <http://ibbtek.altervista.org/XML2JTree> under MIT
 * license.
 */
package xml;

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.io.IOException;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

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

public class XmlToJtree {

	private Document document;
	private DefaultTreeModel treeModel;
	private JTree treeView;

	public XmlToJtree(String filePath) {
		if (filePath != null) {
			document = getDomFromFile(filePath);
		}
		if (document != null) {
			treeModel = new DefaultTreeModel(buildTreeNode(document));
		}
		if (treeModel != null) {
			treeView = new JTree(treeModel);
		}
	}

	private DefaultMutableTreeNode buildTreeNode(Node rootNode) {
		DefaultMutableTreeNode treeNode = new DefaultMutableTreeNode(
				rootNode.getNodeName());
		NodeList children = rootNode.getChildNodes();

		for (int i = 0; i < children.getLength(); i++) {
			Node node = children.item(i);
			short nodeType = node.getNodeType();

			if (nodeType == Node.ELEMENT_NODE) {
				treeNode.add(buildTreeNode(node));

				// FIXME attributes should be leaves of their nodes
				if (node.hasAttributes()) {
					NamedNodeMap attributes = node.getAttributes();
					for (int j = 0; j < attributes.getLength(); j++) {
						Node attr = attributes.item(j);
						treeNode.add(new DefaultMutableTreeNode("@" + attr));
					}
				}
			} else if (nodeType == Node.TEXT_NODE) {
				String text = node.getTextContent().trim();
				if (!text.equals("")) {
					treeNode.add(new DefaultMutableTreeNode(text));
				}
			} else if (nodeType == Node.COMMENT_NODE) {
				String comment = node.getNodeValue().trim();
				treeNode.add(new DefaultMutableTreeNode("#" + comment));
			}
		}
		return treeNode;
	}

	private Document getDomFromFile(String filePath) {
		Document document = null;
		try {
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			document = dbf.newDocumentBuilder().parse(filePath);
			document.normalizeDocument();
		} catch (IOException | ParserConfigurationException | SAXException e) {
			e.printStackTrace();
		}
		return document;
	}

	public void showPopUp(String title, int width, int height) {
		if (treeView != null) {
			JFrame frame = new JFrame();
			frame.setTitle(title);
			frame.setSize(width, height);
			frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
			frame.setLocationRelativeTo(null);
			frame.add(new JScrollPane(treeView));
			frame.add(new JPanel(new GridLayout(1, 1)), BorderLayout.SOUTH);
			frame.setVisible(true);
		}
	}

	public static void main(String[] args) {
		XmlToJtree x2j = new XmlToJtree("simple.xml");
		x2j.showPopUp("XML", 400, 600);
	}
}