import java.awt.*;

//
// Dialog class
//
class ResultDialog extends Dialog
{
  // Label for the total so far
  private Label totalSoFarLable = new Label ();

  // Continue button
  private Button continueButton = new Button ("Continue");

  // Exit button
  private Button exitButton = new Button ("Exit");

  // Constructor
  ResultDialog (Adder parentFrame)
    {
      // Call the parent constructor, passing the parent frame
      // reference, title, and true (for setting the modal true for
      // the dialog).
      super (parentFrame, 
             "The total so far ....", 
             true);
      
      // Set the layout
      setLayout (new FlowLayout ());

      // Set the result label
      totalSoFarLable.setText ("The total so far is " + 
                               parentFrame.totalSoFar + 
                               " " +
                               "Would you like to keep adding?");
      
      //
      // Add the components
      //

      // Add the label
      add (totalSoFarLable);

      // Add the continue button
      add (continueButton);

      // Add the exit button
      add (exitButton);      
    }

  // Handle the actions on the dialog
  public boolean action (Event event, Object what)
    {
      // If the action was on the add button
      if (event.target == continueButton)
        {
          // Remove the dialog window
          dispose ();
        }
      // If the action was on the exit button
      else if (event.target == exitButton)
        {
          // Close down
          System.exit (0);
        }
      
      // return true
      return true;
    }
}

//
// Frame class
// 
public class Adder extends Frame
{
  // The welcome label
  private Label welcomeLabel = new Label ("Welcome to the Adder application!");
  
  // The instructions
  private Label instructionsLabel = new Label ("Enter a number and I will keep track of the total for you");

  // The add button
  private Button addButton = new Button ("Add");

  // The text field for adding the numbers
  private TextField numberField = new TextField (20);

  // The total so far
  public int totalSoFar;

  // The label for the total so far
  private Label totalSoFarLable = new Label ("The total so far is " + 
                                             totalSoFar);

  // Frame constructor
  public Adder ()
    {
      // Call the super class, and set the window label
      super ("Adder Demo");
      
      // Set the layout manager
      setLayout (new FlowLayout ());
      
      // Add the welcome label
      add (welcomeLabel);

      // Add the instruction label
      add (instructionsLabel);
      
      // Add the number field
      add (numberField);

      // Add the add button
      add (addButton);

      // Add the total so far
      add (totalSoFarLable);
    }

  // Handle the actions on the Frame
  public boolean action (Event event, Object what)
    {
      // If the action was on the add button
      if (event.target == addButton)
        {
          try
            {
              // Get the number entered by the user
              int currentNumber = Integer.parseInt (numberField.getText ());              
              
              // Add to current total
              totalSoFar += currentNumber;

              // Create the dialog
              ResultDialog resultDialog = new ResultDialog (this);
              
              // Size it properly
              resultDialog.resize (300, 100);
              
              // Show the dialog box
              resultDialog.show ();
              
              // Reset the number field
              numberField.setText ("");

              // Reset the total label
              totalSoFarLable.setText ("The total so far is " + 
                                       totalSoFar);      
            }
          catch (Exception exception)
            {
              // Indicate error
              totalSoFarLable.setText ("Incorrect number entered! Try again!!");
            }
        }

      // return true
      return true;
    }

  public static void main (String[] args)
    {
      // Create the adder
      Adder adder = new Adder ();

      // Resize
      adder.resize (300, 200);

      // Show the frame
      adder.show ();
    }
}