import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.util.Random;

import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class Assign6 extends JApplet implements ActionListener
{

// graphical user interface components
JLabel questionLabel;
JTextField questionField;

// constant variable
int number1;
int number2;
boolean product = true;
final int CORRECT = 0, INCORRECT = 1;
int productStatus = CORRECT;
private int correctAnswer;
private int userAnswer;


public void init()
{
// obtain content pane and change its layout to FlowLayout
Container container = getContentPane();
container.setLayout( new FlowLayout() );

// create label and text field for question
questionLabel = new JLabel( "How much is " + number1 + " times " + number2 + "?");
container.add( questionLabel );
questionField = new JTextField( 10 );
questionField.setEditable( true );
container.add( questionField );

} // end method init

public void generateQuestion()
{
Random randomNumber = new Random();

// pick random numbers
int number1 = 1 + randomNumber.nextInt(9);
int number2 = 1 + randomNumber.nextInt(9);
correctAnswer = number1 * number2;

// display results in textfields
questionField.setText( Integer.toString( number1 ) );
questionField.setText( Integer.toString( number2 ) );

} // end method generateQuestion

public void actionPerformed ( ActionEvent actionEvent )
{
userAnswer = Integer.parseInt(questionField.getText());

// first roll of dice
if ( product )
{

switch ( userAnswer )
{

// user inputs correct product
case 1:
userAnswer = correctAnswer;
productStatus = CORRECT;
questionField.setText( "" ); // clear point field
break;

// user inputs incorrect product
case 2:
userAnswer = correctAnswer;
productStatus = INCORRECT;
questionField.setText( "" ); // clear point field
break;

} // end switch

}

} // end method actionPerformed

public void displayMessage()
{
if( userAnswer == correctAnswer )
{
showStatus( "Very good!" );
generateQuestion();
} // end if
else
{
showStatus( "No. Please try again." );
} // end else


} // end method displayMessage

} // end class Assign6

if (userAnswer == correctAnswer) { do correct stuff } else { do wrong stuff }

// graphical user interface components
JLabel questionLabel;
JTextField questionField;

// constant variable
private int correctAnswer;
private int userAnswer;

questionField.addActionListener(new ActionListener(){...});

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class TutorApplet extends JApplet
{
private JPanel contentPane;
private JTextField answerField;
private JLabel questionField, responseField;
private Tutor tutor;

public TutorApplet(Tutor tutor)
{
this.tutor = tutor;
}

public void init()
{
contentPane = new JPanel();
contentPane.setLayout(new FlowLayout());
answerField = new JTextField("",2);
answerField.setEditable(true);
answerField.addActionListener(
new ActionListener(){
public void actionPerformed(ActionEvent e)
{
int answer = Integer.parseInt(answerField.getText());
String response = tutor.judgeExpression(answer);
answerField.setText("");
questionField.setText(tutor.getMultiplicationExpression().toString());
responseField.setText(response);
}});
questionField = new JLabel(tutor.getMultiplicationExpression().toString());
responseField = new JLabel("");

contentPane.add(questionField);
contentPane.add(answerField);
contentPane.add(responseField);
this.setContentPane(contentPane);

}


}

public abstract class Tutor
{
protected MultiplicationExpression exp;
protected MultiplicationExpressionFactory factory;

public Tutor(MultiplicationExpressionFactory factory)
{
this.factory = factory;
exp = factory.createMultiplicationExpression();
}

public MultiplicationExpression getMultiplicationExpression()
{
return exp;
}

public abstract String judgeExpression(int answer);

}

public class MultiplicationExpression
{
protected int multiplicand, multiplier;
protected RandomNumberGenerator rng;
public MultiplicationExpression(RandomNumberGenerator rng)
{
this.rng = rng;
multiplicand = rng.getRandomNumber();
multiplier = rng.getRandomNumber();
}
public int getAnswer()
{
return multiplicand * multiplier;
}

}

public interface RandomNumberGenerator
{
public int getRandomNumber();
}

public interface MultiplicationExpressionFactory {
public MultiplicationExpression createMultiplicationExpression();
}

public class MinkoTutorMultiplicationExpressionFactory implements MultiplicationExpressionFactory {
public MultiplicationExpression createMultiplicationExpression()
{
return new MinkoTutorMultiplicationExpression();
}
}

public class MinkoTutorMultiplicationExpression extends MultiplicationExpression
{
public MinkoTutorMultiplicationExpression()
{
super(new MinkoTutorRandomNumberGenerator());

}

public String toString()
{
return String.format("How much is %d times %d?",multiplicand,multiplier);
}
}

public class MinkoTutor extends Tutor{

public MinkoTutor()
{
super(new MinkoTutorMultiplicationExpressionFactory());
}

public String judgeExpression(int answer)
{
boolean result = answer == exp.getAnswer();

if(result) exp = factory.createMultiplicationExpression();

return result ? "Good Job!" : "Try Again!";

}

}

public class MinkoTutorApplet extends TutorApplet
{
public MinkoTutorApplet()
{
super(new MinkoTutor());
}
}

public class MinkoTutorRandomNumberGenerator implements RandomNumberGenerator
{
public int getRandomNumber()
{
return 1 + (int)(Math.random() * 9);
}
}