import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Exercise22_6 extends JApplet {
  private LinkedList list = new LinkedList();
  private JTextField jtfNumber = new JTextField(8);
  private JTextArea jtaNumbers = new JTextArea();
  private JButton jbtSort = new JButton("Sort");
  private JButton jbtShuffle = new JButton("Shuffle");
  private JButton jbtReverse = new JButton("Reverse");

  public Exercise22_6() {
    JPanel panel1 = new JPanel();
    panel1.add(new JLabel("Enter a number: "));
    panel1.add(jtfNumber);

    JScrollPane jsp = new JScrollPane(jtaNumbers);

    JPanel panel2 = new JPanel();
    panel2.add(jbtSort);
    panel2.add(jbtShuffle);
    panel2.add(jbtReverse);

    add(panel1, BorderLayout.NORTH);
    add(jsp, BorderLayout.CENTER);
    add(panel2, BorderLayout.SOUTH);

    jtfNumber.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        if (!list.contains(new Integer(jtfNumber.getText()))) {
          jtaNumbers.append(jtfNumber.getText() + " ");
          list.add(new Integer(jtfNumber.getText()));
        }
      }
    });

    jbtSort.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        Collections.sort(list);
        display();
      }
    });

    jbtShuffle.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        Collections.shuffle(list);
        display();
      }
    });

    jbtReverse.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        Collections.reverse(list);
        display();
      }
    });
  }

  private void display() {
    jtaNumbers.setText(null);
    ListIterator iterator = list.listIterator();
    while (iterator.hasNext()) {
      jtaNumbers.append(iterator.next() + " ");
    }
  }

  public static void main(String[] args) {
    Exercise22_6 applet = new Exercise22_6();
    JFrame frame = new JFrame();
    //EXIT_ON_CLOSE == 3
    frame.setDefaultCloseOperation(3);
    frame.setTitle("Exercise22_6");
    frame.add(applet, BorderLayout.CENTER);
    applet.init();
    applet.start();
    frame.setSize(600, 160);
    frame.setLocationRelativeTo(null); // Center the frame
    frame.setVisible(true);
  }
}