Java Swing How to - Change mouse cursor on hover over node in JTree

Question

We would like to know how to change mouse cursor on hover over node in JTree.
Answer

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.Desktop;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.net.URI;
/*from  w ww  .ja v  a  2 s. c  om*/
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.text.AttributeSet;
import javax.swing.text.Element;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLDocument;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeCellRenderer;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;

public class Main {
  private static TreeModel getTreeModel() {
    return new DefaultTreeModel(getNodes(new DefaultMutableTreeNode(
        "<html>Root <a href=\"http://www.google.be\">Google</a></html>"), 5));
  }

  private static TreeNode getNodes(DefaultMutableTreeNode parent, int i) {
    if (i > 0) {
      for (int j = 0; j < 5; j++) {
        DefaultMutableTreeNode newChild = new DefaultMutableTreeNode(
            "<html>Node "
                + (j + 1)
                + " <a href=\"http://www.java2s.com\">java2s.com</a></html> and text");
        getNodes(newChild, i - 1);
        parent.add(newChild);
      }
    }
    return parent;
  }

  public static void main(String[] args) throws Exception {
    final JTree tree = new JTree(getTreeModel());
    tree.setCellRenderer(new MyTreeCellRenderer());
    HyperlinkMouseListener listener = new HyperlinkMouseListener(tree);
    tree.addMouseListener(listener);
    tree.addMouseMotionListener(listener);
    JFrame f = new JFrame(Main.class.getSimpleName());
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.add(new JScrollPane(tree), BorderLayout.CENTER);
    f.pack();
    f.setSize(f.getWidth() + 100, f.getHeight() + 100);
    f.setVisible(true);
  }

}

class MyTreeCellRenderer extends DefaultTreeCellRenderer implements
    TreeCellRenderer {

  private JEditorPane editorPane;

  public MyTreeCellRenderer() {
    editorPane = new JEditorPane("text/html", null);
  }

  @Override
  public Component getTreeCellRendererComponent(JTree tree, Object value,
      boolean selected, boolean expanded, boolean leaf, int row,
      boolean hasFocus) {
    Component c = super.getTreeCellRendererComponent(tree, value, selected,
        expanded, leaf, row, hasFocus);
    if (c instanceof JLabel) {
      JLabel label = (JLabel) c;
      editorPane.setText(label.getText());
      editorPane.setToolTipText(label.getToolTipText());
      editorPane.setOpaque(label.isOpaque());
      editorPane.setBackground(label.getBackground());
      editorPane.setBorder(label.getBorder());
    }
    return editorPane;
  }
}

class HyperlinkMouseListener extends MouseAdapter {
  JTree tree;

  public HyperlinkMouseListener(JTree tree) {
    this.tree = tree;
  }

  @Override
  public void mouseExited(MouseEvent e) {
    tree.setCursor(Cursor.getDefaultCursor());
  }

  @Override
  public void mouseClicked(MouseEvent e) {
    Element h = getHyperlinkElement(e);
    if (h != null) {
      Object attribute = h.getAttributes().getAttribute(HTML.Tag.A);
      if (attribute instanceof AttributeSet) {
        AttributeSet set = (AttributeSet) attribute;
        String href = (String) set.getAttribute(HTML.Attribute.HREF);
        if (href != null) {
          try {
            Desktop.getDesktop().browse(new URI(href));
          } catch (Exception e1) {
            e1.printStackTrace();
          } 
        }
      }
    }
  }

  @Override
  public void mouseMoved(MouseEvent event) {
    boolean isHyperlink = isHyperlink(event);
    if (isHyperlink) {
      tree.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
    } else {
      tree.setCursor(Cursor.getDefaultCursor());
    }

  }

  private boolean isHyperlink(MouseEvent event) {
    return getHyperlinkElement(event) != null;
  }

  private Element getHyperlinkElement(MouseEvent event) {
    Point p = event.getPoint();
    int selRow = tree.getRowForLocation(p.x, p.y);
    TreeCellRenderer r = tree.getCellRenderer();
    if (selRow == -1 || r == null) {
      return null;
    }
    TreePath path = tree.getPathForRow(selRow);
    Object lastPath = path.getLastPathComponent();
    Component rComponent = r.getTreeCellRendererComponent(tree, lastPath, tree
        .isRowSelected(selRow), tree.isExpanded(selRow), tree.getModel()
        .isLeaf(lastPath), selRow, true);

    if (rComponent instanceof JEditorPane == false) {
      return null;
    }
    Rectangle pathBounds = tree.getPathBounds(path);
    JEditorPane editor = (JEditorPane) rComponent;
    editor.setBounds(tree.getRowBounds(selRow));
    p.translate(-pathBounds.x, -pathBounds.y);
    int pos = editor.getUI().viewToModel(editor, p);
    if (pos >= 0 && editor.getDocument() instanceof HTMLDocument) {
      HTMLDocument hdoc = (HTMLDocument) editor.getDocument();
      Element elem = hdoc.getCharacterElement(pos);
      if (elem.getAttributes().getAttribute(HTML.Tag.A) != null) {
        return elem;
      }
    }
    return null;
  }
}