import javax.swing.*;import java.awt.*;public class GraphDepthFirstSearch extends JFrame {  JPanel jPanel1 = new JPanel();  public GraphDepthFirstSearch() {    DepthFirstSearch engine = new DepthFirstSearch();	  // Define a test network before calling the super class 'init':	  engine.addNode("0", 20, 40);	  engine.addNode("1", 60, 60);	  engine.addNode("2", 100, 40);	  engine.addNode("3", 50, 110);	  engine.addNode("4", 140, 80);	  engine.addNode("5", 160, 150);	  engine.addNode("6", 200, 80);	  engine.addNode("7", 160, 40);	  engine.addNode("8", 240, 120);	  engine.addNode("9", 260, 90);	  engine.addLink(0,1);	  engine.addLink(1,2);	  engine.addLink(2,3);	  engine.addLink(2,4);	  engine.addLink(4,5);	  engine.addLink(4,6);	  engine.addLink(6,8);	  engine.addLink(8,9);	  engine.addLink(2,7);	  engine.addLink(7,9);          System.out.println("Before calculating path");          path = engine.findPath(0, 9);          System.out.println("After calculating path:");          for (int i=0; i<path.length; i++) {            System.out.println("  node # " + path[i]);          }          this.engine = engine;    try {      jbInit();    }    catch(Exception e) {      e.printStackTrace();    }  }  private int [] path = null;  private DepthFirstSearch engine = null;  public static void main(String[] args) {    GraphDepthFirstSearch graphDepthFirstSearch1 = new GraphDepthFirstSearch();  }  private void jbInit() throws Exception {    this.setDefaultCloseOperation(3);    jPanel1.setBackground(Color.white);    this.getContentPane().add(jPanel1, BorderLayout.CENTER);    this.setSize(290, 180);    this.setVisible(true);  }    protected void paintNode(Graphics g, String name, int x, int y) {	int len = name.length() * 10 + 6;	int x1 = x - (len / 2);	int x2 = x + (len / 2);	int y1 = y - 10;	int y2 = y + 10;	g.setColor(Color.cyan);	g.fill3DRect(x1, y1, len, 20, true);	g.setColor(Color.black);	g.drawString(name, x1 + 4, y2 - 6);    }    public void paint(Graphics g) {	super.paint(g);	if (engine != null && path != null) {            int numNodes = engine.getNumNodes();            int numLinks = engine.getNumLinks();            for (int i=0; i<numLinks; i++) {               int l1 = engine.getLink1(i);               int l2 = engine.getLink2(i);               int x1 = engine.getNodeX(l1);               int y1 = engine.getNodeY(l1);               int x2 = engine.getNodeX(l2);               int y2 = engine.getNodeY(l2);               g.setColor(Color.lightGray);               g.drawLine(x1, y1, x2, y2);            }            for (int i=1; i<path.length; i++) {               int x1 = engine.getNodeX(path[i-1]);               int y1 = engine.getNodeY(path[i-1]);               int x2 = engine.getNodeX(path[i]);               int y2 = engine.getNodeY(path[i]);               g.setColor(Color.black);               g.drawLine(x1, y1, x2, y2);            }            for (int i=0; i<numNodes; i++) {               int x1 = engine.getNodeX(i);               int y1 = engine.getNodeY(i);               paintNode(g, engine.getNodeName(i), x1, y1);            }        }    }}