TreePainter demo

package treePainter;

import java.awt.EventQueue;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import java.awt.Toolkit;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.plaf.basic.BasicInternalFrameTitlePane.MaximizeAction;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

class TreeNode {
    int data;
    TreeNode left, right;
    static int maxDepth;
    public TreeNode(int d) {
        data = d;
        left = right = null;
    }
    public TreeNode(int d, TreeNode l, TreeNode r) {
        data = d;
        left = l;
        right = r;
    }
    public static void printTree(TreeNode node) {
        if (node != null) {
            printTree(node.left);
            System.out.println(node.data);
            printTree(node.right);
        }
    }
    public static TreeNode insertTree(TreeNode node, int d) {
        TreeNode last=null;
        int depth=0;
        while (node!=null) {
            last = node;
            if (d>node.data) node=node.right;
            else if (d<node.data) node=node.left;
            else return null;
            if (++depth>maxDepth) maxDepth=depth;
        }
        TreeNode newnode = new TreeNode(d);
        if (last!=null) {
            if (d>last.data) last.right=newnode;
            else last.left = newnode;
        }
        return newnode;
    }
}


public class Main {

    private JFrame frmTreePainter;
    private JTextField textField;
    public int levels;

    class painter extends JPanel {

        void drawTree(TreeNode node, Graphics g, int x, int y, int level) {
            if (level > 0 && node!=null) {
                int d=10 * (1 << level);
                drawTree(node.left, g, x - d, y + 20, level - 1);
                g.drawOval(x, y, 15, 15);
                g.drawString(""+node.data, x, y+10);
                drawTree(node.right, g, x + d, y + 20, level - 1);
            }
        }

        @Override
        public void paint(Graphics g) {
            // TODO Auto-generated method stub
            super.paint(g);
            g.drawLine(0, 0, 100, 100);
            drawTree(tree, g, getWidth()/2, 0, tree.maxDepth+1);

        }

    }

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Main window = new Main();
                    window.frmTreePainter.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public Main() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    TreeNode tree;
    private void initialize() {
        frmTreePainter = new JFrame();
        frmTreePainter.setIconImage(Toolkit.getDefaultToolkit()
                .getImage(Main.class.getResource("/javax/swing/plaf/basic/icons/image-delayed.png")));
        frmTreePainter.setTitle("Tree painter");
        frmTreePainter.setBounds(100, 100, 450, 300);
        frmTreePainter.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        frmTreePainter.getContentPane().add(panel, BorderLayout.NORTH);

        JLabel lblNewLabel = new JLabel("Depth:");
        panel.add(lblNewLabel);

        textField = new JTextField();
        textField.setText("5");
        panel.add(textField);
        textField.setColumns(10);

        JButton btnPaintIt = new JButton("Paint it!");
        btnPaintIt.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                System.out.println("You clicked on me!!");
                String number = textField.getText();
                levels = Integer.parseInt(number);
                TreeNode t=TreeNode.insertTree(tree, levels);
                if (tree==null) tree=t;
                frmTreePainter.repaint();
                System.out.println("Number is=" + number);
            }
        });
        panel.add(btnPaintIt);

        painter panel_1 = new painter();
        frmTreePainter.getContentPane().add(panel_1, BorderLayout.CENTER);
    }

}