How to highlight node in JTree?

Question

After the tree has been displayed, I want to highlight the nodes matching some certain keywords. How to implement that? Nothing useful is found in past threads.
thanks.

Answer 1

to take a wild guess:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
public class HighlightTreeNodeTest {
  private final JTree tree       = new JTree();
  private final JTextField field = new JTextField("foo");
  private final JButton button   = new JButton();
  private final MyTreeCellRenderer renderer =
    new MyTreeCellRenderer(tree.getCellRenderer());
  public JComponent makeUI() {
    field.getDocument().addDocumentListener(new DocumentListener() {
      @Override public void insertUpdate(DocumentEvent e) {
        fireDocumentChangeEvent();
      @Override public void removeUpdate(DocumentEvent e) {
        fireDocumentChangeEvent();
      @Override public void changedUpdate(DocumentEvent e) {}
    tree.setCellRenderer(renderer);
    renderer.q = field.getText();
    fireDocumentChangeEvent();
    JPanel p = new JPanel(new BorderLayout(5, 5));
    p.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
    p.add(field, BorderLayout.NORTH);
    p.add(new JScrollPane(tree));
    return p;
  private void fireDocumentChangeEvent() {
    String q = field.getText();
    renderer.q = q;
    TreePath root = tree.getPathForRow(0);
    collapseAll(tree, root);
    if (!q.isEmpty()) searchTree(tree, root, q);
    tree.repaint();
  private static void searchTree(JTree tree, TreePath path, String q) {
    TreeNode node = (TreeNode)path.getLastPathComponent();
    if (node==null) return;
    if (node.toString().startsWith(q)) tree.expandPath(path.getParentPath());
    if (!node.isLeaf() && node.getChildCount()>=0) {
      Enumeration e = node.children();
      while (e.hasMoreElements())
        searchTree(tree, path.pathByAddingChild(e.nextElement()), q);
  private static void collapseAll(JTree tree, TreePath parent) {
    TreeNode node = (TreeNode)parent.getLastPathComponent();
    if (!node.isLeaf() && node.getChildCount()>=0) {
      Enumeration e = node.children();
      while (e.hasMoreElements()) {
        TreeNode n = (TreeNode)e.nextElement();
        TreePath path = parent.pathByAddingChild(n);
        collapseAll(tree, path);
    tree.collapsePath(parent);
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() { createAndShowGUI(); }
  public static void createAndShowGUI() {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    f.getContentPane().add(new HighlightTreeNodeTest().makeUI());
    f.setSize(320, 240);
    f.setLocationRelativeTo(null);
    f.setVisible(true);
class MyTreeCellRenderer extends DefaultTreeCellRenderer {
  private final TreeCellRenderer renderer;
  public String q;
  public MyTreeCellRenderer(TreeCellRenderer renderer) {
    this.renderer = renderer;
  @Override public Component getTreeCellRendererComponent(
      JTree tree, Object value, boolean isSelected, boolean expanded,
      boolean leaf, int row, boolean hasFocus) {
    JComponent c = (JComponent)renderer.getTreeCellRendererComponent(
        tree, value, isSelected, expanded, leaf, row, hasFocus);
    if (isSelected) {
      c.setOpaque(false);
      c.setForeground(getTextSelectionColor());
    } else {
      c.setOpaque(true);
      if (q!=null && !q.isEmpty() && value.toString().startsWith(q)) {
        c.setForeground(getTextNonSelectionColor());
        c.setBackground(Color.YELLOW);
      } else {
        c.setForeground(getTextNonSelectionColor());
        c.setBackground(getBackgroundNonSelectionColor());
    return c;
}