restaurantbillcalculator.java

这是一个ATM的程序

// Exercise 26.16: RestaurantBillCalculator.java
// Calculates a table's bill.
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import java.text.*;
import java.util.*;
import javax.swing.*;

public class RestaurantBillCalculator extends JFrame
{
   // JLabel for Restaurant
   private JLabel restaurantJLabel;

   // JPanel for Waiter Information
   private JPanel waiterJPanel;

   // JLabel and JComboBox for Table Number
   private JLabel tableNumberJLabel;
   private JComboBox tableNumberJComboBox;

   // JLabel and JTextField for Waiter Name
   private JLabel waiterNameJLabel;
   private JTextField waiterNameJTextField;

   // JPanel for Menu Items
   private JPanel menuItemsJPanel;

   // JLabel and JComboBox for Beverage
   private JLabel beverageJLabel;
   private JComboBox beverageJComboBox; 

   // JLabel and JComboBox for appetizer
   private JLabel appetizerJLabel;
   private JComboBox appetizerJComboBox;

   // JLabel and JComboBox for Main Course
   private JLabel mainCourseJLabel;
   private JComboBox mainCourseJComboBox;

   // JLabel and JComboBox for Dessert
   private JLabel dessertJLabel;
   private JComboBox dessertJComboBox;

   // JLabel and JTextField for Subtotal
   private JLabel subtotalJLabel;
   private JTextField subtotalJTextField; 

   // JLabel and JTextField for Tax
   private JLabel taxJLabel;
   private JTextField taxJTextField;

   // JLabel and JTextField for Total
   private JLabel totalJLabel;
   private JTextField totalJTextField;

   // JButton for Save Table
   private JButton saveTableJButton;

   // JButton for Calculate Bill
   private JButton calculateBillJButton; 

   // JButton for Pay Bill
   private JButton payBillJButton;

   // constant for tax rate
   private final static double TAX_RATE = 0.05;

   // declare instance variables for database processing
   private Connection myConnection;
   private Statement myStatement;
   private ResultSet myResultSet;

   // other instance variables
   private ArrayList billItems = new ArrayList();
   private double subtotal;

   // constructor
   public RestaurantBillCalculator(
      String databaseDriver, String databaseURL )
   {
      // make database connection
      try
      {
         // load Cloudscape driver
         Class.forName( databaseDriver );

         // connect to database
         myConnection = DriverManager.getConnection( databaseURL );

         // create statement
         myStatement = myConnection.createStatement();  
      }
      catch ( SQLException exception )
      {
         exception.printStackTrace();
      }
      catch ( ClassNotFoundException exception )
      {
         exception.printStackTrace();
      }

      // set up GUI
      createUserInterface();

   } // end constructor

   // create and position GUI components; register event handlers
   private void createUserInterface()
   {
      // get content pane for attaching GUI components
      Container contentPane = getContentPane();

      // enable explicit positioning of GUI components
      contentPane.setLayout( null );

      // set up restaurantJLabel
      restaurantJLabel = new JLabel();
      restaurantJLabel.setBounds( 80, 8, 128, 24 );
      restaurantJLabel.setText( "Restaurant" );
      restaurantJLabel.setFont( 
         new Font( "SansSerif", Font.BOLD, 16 ) );
      contentPane.add( restaurantJLabel );

      // set up waiterJPanel
      createWaiterJPanel();
      contentPane.add( waiterJPanel );
      
      // set up menuItemsJPanel
      createMenuItemsJPanel();
      contentPane.add( menuItemsJPanel );

      // set up subtotalJLabel
      subtotalJLabel = new JLabel();
      subtotalJLabel.setBounds( 15, 340, 56, 16 );
      subtotalJLabel.setText( "Subtotal:" );
      contentPane.add( subtotalJLabel );

      // set up subtotalJTextField
      subtotalJTextField = new JTextField();
      subtotalJTextField.setBounds( 70, 340, 80, 20 );
      subtotalJTextField.setEditable( false );
      subtotalJTextField.setBorder( 
         BorderFactory.createLoweredBevelBorder() );
      subtotalJTextField.setHorizontalAlignment( JTextField.RIGHT );
      contentPane.add( subtotalJTextField );

      // set up taxJLabel
      taxJLabel = new JLabel();
      taxJLabel.setBounds( 15, 372, 56, 16 );
      taxJLabel.setText( "Tax:" );
      contentPane.add( taxJLabel );

      // set up taxJTextField
      taxJTextField = new JTextField();
      taxJTextField.setBounds( 70, 372, 80, 20 );
      taxJTextField.setEditable( false );
      taxJTextField.setBorder( 
         BorderFactory.createLoweredBevelBorder() );
      taxJTextField.setHorizontalAlignment( JTextField.RIGHT );
      contentPane.add( taxJTextField );

      // set up totalJLabel
      totalJLabel = new JLabel();
      totalJLabel.setBounds( 15, 404, 56, 16 );
      totalJLabel.setText( "Total:" );
      contentPane.add( totalJLabel );

      // set up totalJTextField
      totalJTextField = new JTextField();
      totalJTextField.setBounds( 70, 404, 80, 20 );
      totalJTextField.setEditable( false );
      totalJTextField.setBorder( 
         BorderFactory.createLoweredBevelBorder() );
      totalJTextField.setHorizontalAlignment( JTextField.RIGHT );
      contentPane.add( totalJTextField );

      // set up saveTableJButton
      saveTableJButton = new JButton();
      saveTableJButton.setBounds( 167, 328, 90, 24 );
      saveTableJButton.setText( "Save Table" );
      saveTableJButton.setBorder( 
         BorderFactory.createRaisedBevelBorder() );
      saveTableJButton.setEnabled( false );
      contentPane.add( saveTableJButton );
      saveTableJButton.addActionListener(

         new ActionListener()  // anonymous inner class
         {
            // event handler called when saveTableJButton is clicked
            public void actionPerformed( ActionEvent event ) 
            {
               saveTableJButtonActionPerformed( event );
            }

         } // end annoymous inner class

      ); // end addActionListener

      // set up calculateBillJButton
      calculateBillJButton = new JButton();
      calculateBillJButton.setBounds( 167, 360, 90, 24 );
      calculateBillJButton.setText( "Calculate Bill" );
      calculateBillJButton.setBorder( 
         BorderFactory.createRaisedBevelBorder() );
      calculateBillJButton.setEnabled( false );
      contentPane.add( calculateBillJButton );
      calculateBillJButton.addActionListener(

         new ActionListener()  // anonymous inner class
         {
            // event handler called when calculateBillJButton 
            // is clicked
            public void actionPerformed( ActionEvent event ) 
            {
               calculateBillJButtonActionPerformed( event );
            }

         } // end anonymous inner class

      ); // end addActionListener

      // set up payBillJButton
      payBillJButton = new JButton();
      payBillJButton.setBounds( 167, 392, 90, 24 );
      payBillJButton.setText( "Pay Bill" );
      payBillJButton.setBorder( 
         BorderFactory.createRaisedBevelBorder() );
      payBillJButton.setEnabled( false );
      contentPane.add( payBillJButton );
      payBillJButton.addActionListener(

         new ActionListener()  // anonymous inner class
         {
            // event handler called when payBillJButton is clicked
            public void actionPerformed( ActionEvent event ) 
            {
               payBillJButtonActionPerformed( event );
            }

         } // end anonymous inner class

      ); // end addActionListener

      // set properties of application's window
      setTitle( "Restaurant Bill Calculator" ); // set window title
      setSize( 280, 500 ); // set window size
      setVisible( true );  // display window

      // ensure database connection is closed 
      // when user quits application
      addWindowListener(

         new WindowAdapter()  // anonymous inner class
         {
            // event handler called when close button is clicked
            public void windowClosing( WindowEvent event )
            {
               frameWindowClosing( event );
            }

         } // end anonymous inner class

      ); // end addWindowListener

   } // end method createUserInterface

   // set up waiterJPanel
   private void createWaiterJPanel()
   {
      waiterJPanel = new JPanel();
      waiterJPanel.setBounds( 20, 48, 232, 88 );
      waiterJPanel.setBorder( BorderFactory.createTitledBorder( 
         BorderFactory.createEtchedBorder(), 
         "Waiter Information" ) );
      waiterJPanel.setLayout( null );

      // set up tableNumberJLabel
      tableNumberJLabel = new JLabel();
      tableNumberJLabel.setBounds( 35, 24, 90, 16 );
      tableNumberJLabel.setText( "Table number:" );
      waiterJPanel.add( tableNumberJLabel );

      // set up tableNumberJTextField
      tableNumberJComboBox = new JComboBox();
      tableNumberJComboBox.setBounds( 154, 24, 60, 25 );
      waiterJPanel.add( tableNumberJComboBox );
      tableNumberJComboBox.addItemListener(

         new ItemListener()  // anonymous inner class
         {
            // event handler called when item in tableNumberJComboBox
            // is selected
            public void itemStateChanged( ItemEvent event )
            {
               tableNumberJComboBoxItemStateChanged( event );
            }

         } // end anonymous inner class

      ); // end addItemListener

      // add numbers to tableNumberJComboBox
      tableNumberJComboBox.addItem( "" );
      loadTableNumbers();

      // set up waiterNameJLabel
      waiterNameJLabel = new JLabel();
      waiterNameJLabel.setBounds( 35, 56, 90, 16 );
      waiterNameJLabel.setText( "Waiter name:" );
      waiterJPanel.add( waiterNameJLabel );

      // set up waiterNameJTextField
      waiterNameJTextField = new JTextField();
      waiterNameJTextField.setBounds( 128, 56, 88, 21 );
      waiterNameJTextField.setEditable( false );
      waiterNameJTextField.setBorder(
         BorderFactory.createLoweredBevelBorder() );
      waiterJPanel.add( waiterNameJTextField );

   } // end method createWaiterJPanel

   // set up menuItemsJPanel
   private void createMenuItemsJPanel()
   {
      menuItemsJPanel = new JPanel();
      menuItemsJPanel.setBounds( 20, 152, 232, 152 );
      menuItemsJPanel.setEnabled( false );
      menuItemsJPanel.setBorder( BorderFactory.createTitledBorder( 
         BorderFactory.createEtchedBorder(), "Menu Items" ) );
      menuItemsJPanel.setLayout( null );

      
      // set up beverageJLabel
      beverageJLabel = new JLabel();
      beverageJLabel.setBounds( 8, 24, 80, 24 );
      beverageJLabel.setText( "Beverage:" );
      menuItemsJPanel.add( beverageJLabel );
      
      // set up beverageJComboBox
      beverageJComboBox = new JComboBox();
      beverageJComboBox.setBounds( 88, 24, 128, 25 );
      beverageJComboBox.setEnabled( false );
      menuItemsJPanel.add( beverageJComboBox );
      beverageJComboBox.addItemListener(

         new ItemListener()  // anonymous inner class
         {
            // event handler called when item in beverageJComboBox
            // is selected
            public void itemStateChanged( ItemEvent event )
            {
               beverageJComboBoxItemStateChanged( event );
            }

         } // end anonymous inner class

      ); // end addItemListener

      // add items to beverageJComboBox
      beverageJComboBox.addItem( "" );