// Main window for the Sketcher application

 import javax.swing.*;

 import static java.awt.event.InputEvent.*;                             // For modifier constants

 @SuppressWarnings("serial")

 public class SketcherFrame extends JFrame {

   // Constructor

   public SketcherFrame(String title) {

     setTitle(title);                                                   // Set the window title

     setDefaultCloseOperation(EXIT_ON_CLOSE);

     setJMenuBar(menuBar);                                              // Add the menu bar to the window

     JMenu fileMenu = new JMenu("File");                                // Create File menu

     JMenu elementMenu = new JMenu("Elements");                         // Create Elements menu

     fileMenu.setMnemonic('F');                                         // Create shortcut

     elementMenu.setMnemonic('E');                                      // Create shortcut

     // Construct the file drop-down menu

     newItem = fileMenu.add("New");                                      // Add New item

     openItem = fileMenu.add("Open");                                    // Add Open item

     closeItem = fileMenu.add("Close");                                  // Add Close item

     fileMenu.addSeparator();                                            // Add separator

     saveItem = fileMenu.add("Save");                                    // Add Save item

     saveAsItem = fileMenu.add("Save As...");                            // Add Save As item

     fileMenu.addSeparator();                                            // Add separator

     printItem = fileMenu.add("Print");                                  // Add Print item

     // Add File menu accelerators

     newItem.setAccelerator(KeyStroke.getKeyStroke('N',CTRL_DOWN_MASK ));

     openItem.setAccelerator(KeyStroke.getKeyStroke('O', CTRL_DOWN_MASK));

     saveItem.setAccelerator(KeyStroke.getKeyStroke('S', CTRL_DOWN_MASK));

     printItem.setAccelerator(KeyStroke.getKeyStroke('P', CTRL_DOWN_MASK));

     // Construct the Element drop-down menu

     elementMenu.add(lineItem = new JRadioButtonMenuItem("Line", true));

     elementMenu.add(rectangleItem = new JRadioButtonMenuItem("Rectangle", false));

     elementMenu.add(circleItem = new JRadioButtonMenuItem("Circle", false));

     elementMenu.add(curveItem = new JRadioButtonMenuItem("Curve", false));

     ButtonGroup types = new ButtonGroup();

     types.add(lineItem);

     types.add(rectangleItem);

     types.add(circleItem);

     types.add(curveItem);

     // Add element type accelerators

     lineItem.setAccelerator(KeyStroke.getKeyStroke('L', CTRL_DOWN_MASK));

     rectangleItem.setAccelerator(KeyStroke.getKeyStroke('E', CTRL_DOWN_MASK));

     circleItem.setAccelerator(KeyStroke.getKeyStroke('I', CTRL_DOWN_MASK));

     curveItem.setAccelerator(KeyStroke.getKeyStroke('V', CTRL_DOWN_MASK));

     elementMenu.addSeparator();

     JMenu colorMenu = new JMenu("Color");                              // Color submenu

     elementMenu.add(colorMenu);                                        // Add the submenu

     colorMenu.add(redItem = new JCheckBoxMenuItem("Red", false));

     colorMenu.add(yellowItem = new JCheckBoxMenuItem("Yellow", false));

     colorMenu.add(greenItem = new JCheckBoxMenuItem("Green", false));

     colorMenu.add(blueItem = new JCheckBoxMenuItem("Blue", true));

     // Add element color accelerators

     redItem.setAccelerator(KeyStroke.getKeyStroke('R', CTRL_DOWN_MASK));

     yellowItem.setAccelerator(KeyStroke.getKeyStroke('Y', CTRL_DOWN_MASK));

     greenItem.setAccelerator(KeyStroke.getKeyStroke('G', CTRL_DOWN_MASK));

     blueItem.setAccelerator(KeyStroke.getKeyStroke('B', CTRL_DOWN_MASK));

     menuBar.add(fileMenu);                                             // Add the file menu

     menuBar.add(elementMenu);                                          // Add the element menu

   }

   private JMenuBar menuBar = new JMenuBar();                           // Window menu bar

   // File menu items

   private JMenuItem newItem,  openItem,   closeItem,

                     saveItem, saveAsItem, printItem;

   // Element menu items

   private JRadioButtonMenuItem lineItem,  rectangleItem, circleItem,   // Types

                                curveItem, textItem;

   private JCheckBoxMenuItem    redItem,   yellowItem,                  // Colors

                                greenItem, blueItem ;

 }

 // Sketching application

 import javax.swing.*;

 import java.awt.*;

 import javax.swing.SwingUtilities;

 public class Sketcher {

   public static void main(String[] args) {

     SwingUtilities.invokeLater(new Runnable() {

             public void run() {

                 createWindow();

             }

         });

   }

   public static void createWindow(){

     window = new SketcherFrame("Sketcher");                            // Create the app window

     Toolkit theKit = window.getToolkit();                              // Get the window toolkit

     Dimension wndSize = theKit.getScreenSize();                        // Get screen size

     // Set the position to screen center & size to half screen size

     window.setSize(wndSize.width/2, wndSize.height/2);                 // Set window size

     window.setLocationRelativeTo(null);                                // Center window

     window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

     window.setVisible(true);

   }

   private static SketcherFrame window;                                 // The application window

 }