Identifying the index of selected XML node from JTree

Question

I have a JTree where the input XML file is mapped into it.

library_system.xml

<library>
    <user>
        <name>Dinesh</name>
        <book>
            <info name="java">Java: The Complete Reference, 9th Edition</info>
            <info name="price">700</info>
            <details>
                <parameter name="author">Herbert Schildt</parameter>
                <parameter name="isbn">9339212096</parameter>
                <parameter name="publisher">McGraw Hill Education</parameter>
            </details>
        </book>
        <book>
            <info name="java">Learning Python 3rd Edition</info>
            <info name="price">1020</info>
            <details>
                <parameter name="author">Mark Lutz</parameter>
                <parameter name="isbn">0596513984</parameter>
                <parameter name="publisher">O'Reilly</parameter>
            </details>
        </book>
    </user>
    <user>
        <name>Vignesh</name>
        <book>
            <info name="java">Java: The Complete Reference, 9th Edition</info>
            <info name="price">700</info>
            <details>
                <parameter name="author">Herbert Schildt</parameter>
                <parameter name="isbn">9339212096</parameter>
                <parameter name="publisher">McGraw Hill Education</parameter>
            </details>
        </book>
    </user>
</library>

When any node of XML selected from JTree, I am printing the selected node name and it's parent name.

StackOverFlow.java

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 *
 * @author dsivaji
 */
public class StackOverFlow {

    public DefaultMutableTreeNode rootNode = null;//For writing
    public Element rootElement = null;
    private DocumentBuilder dBuilder = null;
    public Document doc = null;
    private String xmlFileName = null;
    public static DefaultMutableTreeNode lastNode = null;
    static String selctedXmlProperty = "";
    static String primaryCond = "";
    static Map<String, List> conditionsMap = new HashMap<String, List>();


    public StackOverFlow(String xmlFileName) {

        try {
            dBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            doc = dBuilder.newDocument();

            if (rootNode == null) {
                rootElement = doc.createElement("devices");
                doc.appendChild(rootElement);
                rootNode = new DefaultMutableTreeNode(rootElement.getNodeName());
            }
            this.xmlFileName = xmlFileName;
        } catch (Exception e) {
            System.out.println("Exception in the XML document builders at the constructuor of XMLManipulator");
        }
    }

    static DefaultMutableTreeNode parseXML(String xmlFileName) {

        DefaultMutableTreeNode masterRootNode = null;
        DocumentBuilder dBuilder = null;
        Document doc = null;

        try {
            dBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            doc = dBuilder.newDocument();
            doc = dBuilder.parse(xmlFileName);
            if (doc.hasChildNodes()) {
                masterRootNode = getXMLTree(doc.getChildNodes(), null);
            }
        } catch (Exception e) {
            System.out.println("Exception in XML parsing" + e);
            System.out.println("ex : " + e);
            masterRootNode = new DefaultMutableTreeNode("ERROR");
        }

        return masterRootNode;
    }

    private static DefaultMutableTreeNode getXMLTree(NodeList nodeList, DefaultMutableTreeNode treeParent) {

        //This will be assumed to be master one.
        DefaultMutableTreeNode rootParent = null;

        //If treeParent is null, then it called from the main, not a recursive one.
        if (treeParent == null) {
            rootParent = new DefaultMutableTreeNode("");
        } else {
            rootParent = treeParent;
        }

        for (int count = 0; count < nodeList.getLength(); count++) {

            Node tempNode = nodeList.item(count);

            // make sure it's element node.
            if (tempNode.getNodeType() == Node.ELEMENT_NODE) {

                // get node name and value
                String myNodeName = tempNode.getNodeName().toUpperCase();

                DefaultMutableTreeNode parent = new DefaultMutableTreeNode(myNodeName);
                lastNode = parent;
//                System.out.println(tempNode.getNodeName() + " : " + tempNode.getNodeValue());
                //If it has the attributes, then appending it with the parent text 
                if (tempNode.hasAttributes()) {

                    // get attributes names and values
                    NamedNodeMap nodeMap = tempNode.getAttributes();

                    for (int i = 0; i < nodeMap.getLength(); i++) {

                        Node node = nodeMap.item(i);
                        String nodeName = node.getNodeName();
                        if (nodeName.equals("name")) {
                            System.out.println("attr value : " + node.getNodeValue() + ", " + tempNode.getNodeValue());

                            parent.setUserObject(myNodeName + " (" + node.getNodeValue() + ")");
                        }
//                        System.out.print("attr name : " + node.getNodeName());

                    }
                } else {
//                    System.out.println("Node Text content = " + tempNode.getTextContent());
                }

                //Adding it to the root parent of this current context
                rootParent.add(parent);

                if (tempNode.hasChildNodes()) {
                    // loop again if has child nodes and add it to the rootParent
                    rootParent.add(getXMLTree(tempNode.getChildNodes(), parent));
                }
//                System.out.println("Node Name = " + tempNode.getNodeName() + " [CLOSE]");
            } else if (tempNode.getNodeType() == Node.TEXT_NODE) {
                String txtVal = tempNode.getNodeValue().trim();
                if (!txtVal.isEmpty()) {
                    if (lastNode != null) {
                        lastNode.setUserObject(lastNode.getUserObject() + " = " + txtVal);
                    }
                    System.out.println("->" + txtVal + "<-");
                }
            }
        }
        return rootParent;
    }

    public void removeChilds(Node node) {
        while (node.hasChildNodes()) {
            node.removeChild(node.getFirstChild());
        }
    }

    public static void main(String[] args) {
        showGUI("C:\\library_system.xml");
    }

    public static void showGUI(final String logXmlFileName) {
        JFrame topoWindow = new JFrame("Library Info");
        topoWindow.setTitle(logXmlFileName.substring(logXmlFileName.lastIndexOf("\\") + 1));
        topoWindow.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);

        final JTree topoTree = new JTree(parseXML(logXmlFileName));

        topoTree.addTreeSelectionListener(new TreeSelectionListener() {

            public void valueChanged(TreeSelectionEvent e) {
                JTree treeSource = (JTree) e.getSource();
                TreePath tp = e.getNewLeadSelectionPath();

//                System.out.println(Arrays.toString(e.getPaths()));
                System.out.println(e.getPath());
//                System.out.println(tp.getParentPath() + " at " + tp.getPathCount());
                if (tp != null) {

                    TreeNode lastPathComponent = (TreeNode) tp.getLastPathComponent();
                    System.out.println(lastPathComponent.isLeaf());
                    System.out.println("parent -> " + lastPathComponent.getParent().toString());
                    DefaultMutableTreeNode node = (DefaultMutableTreeNode) tp.getLastPathComponent();
                    System.out.println(node.getParent().getIndex(node));
//                    System.out.println("parent ->" + lastPathComponent.getParent().getParent().getChildCount());
                    selctedXmlProperty = tp.getLastPathComponent().toString();
                    System.out.println("val ->" + tp.getLastPathComponent());
                }
            }
        });
        final JScrollPane scrlTreeView = new JScrollPane(topoTree);

        final JPanel pnlLeft = new JPanel(new BorderLayout(5, 5));

        pnlLeft.add(scrlTreeView);

        topoWindow.add(pnlLeft);

        for (int i = 0; i < topoTree.getRowCount(); i++) {
//                System.out.println(topoTree.getPathForRow(i));
            topoTree.expandRow(i);
        }

        topoWindow.pack();
        topoWindow.setLocationRelativeTo(null);
        topoWindow.setSize(500, 500);
        topoWindow.setVisible(true);
    }
}

Output :

[, LIBRARY, USER, BOOK, DETAILS, PARAMETER (author) = Herbert Schildt]
true
parent -> DETAILS
0
val ->PARAMETER (author) = Herbert Schildt

The above messages are due to the following method

public void valueChanged(TreeSelectionEvent e) {
    JTree treeSource = (JTree) e.getSource();
    TreePath tp = e.getNewLeadSelectionPath();
    System.out.println(e.getPath());
    if (tp != null) {
        TreeNode lastPathComponent = (TreeNode) tp.getLastPathComponent();
        System.out.println(lastPathComponent.isLeaf());
        System.out.println("parent -> " + lastPathComponent.getParent().toString());
        DefaultMutableTreeNode node = (DefaultMutableTreeNode) tp.getLastPathComponent();
        System.out.println(node.getParent().getIndex(node));
        selctedXmlProperty = tp.getLastPathComponent().toString();
        System.out.println("val ->" + tp.getLastPathComponent());
    }
}

Here, what should I do to know that a person has selected the 2nd user element's 1st book element's 1st detail element's attribute named author ?

Answer 1

In the valueChanged add the following method call to printDetails :

public void valueChanged(TreeSelectionEvent e) {
                JTree treeSource = (JTree) e.getSource();
                printDetails(e.getNewLeadSelectionPath());//This One
                TreePath tp = e.getNewLeadSelectionPath();

The method printDetails will take the parent of the current node (current node is named me) and try to locate me in the list of children the parent has. Once it found it prints the message with the index and does the same for the parent until it gets to root. If you don't want to work with 0-index add 1 to i before printing it.

private void printDetails(TreePath me) {
                DefaultMutableTreeNode mee = (DefaultMutableTreeNode) me.getLastPathComponent();
                TreePath parent = me.getParentPath();
                if(parent == null){
                    return;
                }
                DefaultMutableTreeNode lastPathComponent = (DefaultMutableTreeNode) (parent.getLastPathComponent());
                for (int i = 0; i < lastPathComponent.getChildCount(); i++) {
                    if (lastPathComponent.getChildAt(i).equals(mee)) {
                        System.out.println(mee.getUserObject() + " I am the " + i + "th child of " + lastPathComponent.getUserObject());
                    }
                }
                printDetails(parent);
            }