I'm developing a JavaSE-1.7 Swing application that displays XML files as a JTree. This will be the base for further work, e.g. filtering nodes.
My questions, as a beginner in Java & Swing & MVC:
- Design: How would you refactor this into Model/View/Controller?
(Doing the doc/tree model stuff inside of the GUI thread isn't best practice, I think.) - Performance: How can I speed up
expandAllNodes()? It eats up ~85% of total time with my 0.5MB target file. - What else could be improved?
Below is my working example:
package xml; import java.awt.BorderLayout; import java.awt.EventQueue; import java.awt.GridLayout; import java.io.File; 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; /** * Uses Ibbtek's code from <http://ibbtek.altervista.org/XML2JTree> under MIT * license. */ public class XmlToJtree { private File file; private Document document; private DefaultTreeModel treeModel; private JTree treeView; /** * Constructor. * * @param filePath */ public XmlToJtree(String path) { if (path != null) { file = new File(path); } if (file != null && file.canRead()) { document = parseDomFromXml(file); } if (document != null) { treeModel = new DefaultTreeModel(buildTreeNode(document)); } if (treeModel != null) { treeView = new JTree(treeModel); } } /** * Expand all tree nodes. */ public void expandAllNodes() { if (treeView != null) { for (int i = 0; i < treeView.getRowCount(); i++) { treeView.expandRow(i); } } } /** * Show window. * * @param title * @param width * @param height */ public void show(String title, int width, int height) { if (treeView != null) { JFrame frame = new JFrame(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.pack(); frame.setVisible(true); } } /** * Recursively build tree node from document node. Add attributes as leaves * * @param docNode * @return A default mutable tree node. */ private DefaultMutableTreeNode buildTreeNode(Node docNode) { DefaultMutableTreeNode treeNode = new DefaultMutableTreeNode( docNode.getNodeName()); if (docNode.hasAttributes()) { NamedNodeMap attributes = docNode.getAttributes(); for (int j = 0; j < attributes.getLength(); j++) { String attr = attributes.item(j).toString(); treeNode.add(new DefaultMutableTreeNode(attr)); } } if (docNode.hasChildNodes()) { NodeList childNodes = docNode.getChildNodes(); for (int i = 0; i < childNodes.getLength(); i++) { Node childNode = childNodes.item(i); short childNodeType = childNode.getNodeType(); if (childNodeType == Node.ELEMENT_NODE) { treeNode.add(buildTreeNode(childNode)); } else if (childNodeType == Node.TEXT_NODE) { String text = childNode.getTextContent().trim(); if (!text.equals("")) { treeNode.add(new DefaultMutableTreeNode(text)); } } else if (childNodeType == Node.COMMENT_NODE) { String comment = childNode.getNodeValue().trim(); treeNode.add(new DefaultMutableTreeNode(comment)); } } } return treeNode; } /** * Parse an XML file into document object model. * * @param filePath * @return A DOM document. */ private Document parseDomFromXml(File file) { Document document = null; try { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); document = dbf.newDocumentBuilder().parse(file); document.normalizeDocument(); } catch (IOException | ParserConfigurationException | SAXException e) { e.printStackTrace(); } return document; } /** * Run the program. * * @param args */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { XmlToJtree x2j = new XmlToJtree("simple.xml"); x2j.expandAllNodes(); x2j.show(x2j.file.getName(), 400, 600); } }); } } Sample XML "simple.xml":
<?xml version="1.0" encoding="utf-8"?> <!-- created by ferkulat --> <MYXML xmlns="namespace"> <Header id="header"></Header> <Product id="product"> <Description id="description">Some text</Description> <Ref id="ref"></Ref> <Data id="data"> <Ref id="ref"></Ref> </Data> <Form id="form"></Form> </Product> </MYXML> And this is the result:
