Chapter 24 Exercise 11, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

24.11 (Animation: doubly linked list) Write a program to animate search, insertion, and deletion in a doubly linked list, as shown in Figure 24.24. The Search button searches the specified value in the list. The Delete button deletes the specified value from the list. The Insert button appends the value into the list if the index is not specified; otherwise, it inserts the value into the specified index in the list. Also add two buttons named Forward Traversal and Backward Traversal for displaying the elements in a forward and backward order, respectively, using iterators.

import javax.swing.*;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Iterator;
import java.util.LinkedList;

public class Exercise11 extends JApplet {

 private static final long serialVersionUID = 1L;
 private DoubleLinkedListAnimation doubleLinkedListAnimation = new DoubleLinkedListAnimation();
 private LinkedList<Integer> list = new LinkedList<>();
 private JTextField jtaValue = new JTextField(5);
 private JTextField jtaIndex = new JTextField(5);
 private int foundedValue = -1;
 
 public Exercise11() {
  add(doubleLinkedListAnimation, BorderLayout.CENTER);
  JPanel jPanel = new JPanel();
  jPanel.add(new JLabel("Enter a value: "));
  jPanel.add(jtaValue);
  jPanel.add(new JLabel("Enter an index: "));
   jPanel.add(jtaIndex);
  JButton jbtSearch = new JButton("Search");
  jPanel.add(jbtSearch);
  JButton jbtInsert = new JButton("Insert");
  jPanel.add(jbtInsert);
  JButton jbtDelete = new JButton("Delete");
  jPanel.add(jbtDelete);
  JButton jbtForward = new JButton("Forward Traversal");
  jPanel.add(jbtForward);
  JButton jbtBackward = new JButton("Backward Traversal");
  jPanel.add(jbtBackward);  
  add(jPanel, BorderLayout.SOUTH);
  
  
  jbtForward.addActionListener(new ActionListener() {   
   @Override
   public void actionPerformed(ActionEvent e) {
    String result = "";
    for (Iterator<Integer> iterator = list.iterator(); iterator.hasNext();) {
     result += iterator.next() + " ";     
    }
    JOptionPane.showMessageDialog(null, "The elements are " + result, "Forward Traversal", JOptionPane.INFORMATION_MESSAGE);    
   }
  });
  
  jbtBackward.addActionListener(new ActionListener() {   
   @Override
   public void actionPerformed(ActionEvent e) {
    String result = "";
    for (Iterator<Integer> iterator = list.descendingIterator(); iterator.hasNext();) {
     result += iterator.next() + " ";     
    }
    JOptionPane.showMessageDialog(null, "The elements are " + result, "Backward Traversal", JOptionPane.INFORMATION_MESSAGE);    
   }
  });
  
  jbtInsert.addActionListener(new ActionListener() {   
   @Override
   public void actionPerformed(ActionEvent e) {
    try {
     int value = Integer.parseInt(jtaValue.getText());
     if(jtaIndex.getText().equals("")) {
      list.add(value);
     } else {
      int index = Integer.parseInt(jtaIndex.getText());
      list.add(index, value);
      jtaIndex.setText("");      
     }
     doubleLinkedListAnimation.repaint(); 
     jtaValue.setText("");
     foundedValue = -1;
     jtaValue.requestFocus();
    } catch (NumberFormatException e2) {
    } catch (IndexOutOfBoundsException e2) {
    }
   }
  });
  
  jbtDelete.addActionListener(new ActionListener() {
   
   @Override
   public void actionPerformed(ActionEvent e) {
    try {
     int value = Integer.parseInt(jtaValue.getText());
     list.remove(new Integer(value));
     foundedValue = -1;
     doubleLinkedListAnimation.repaint();
     jtaValue.setText("");
     jtaValue.requestFocus();
    } catch (NumberFormatException e2) {
    }
   }
  });
  
  jbtSearch.addActionListener(new ActionListener() {
   
   @Override
   public void actionPerformed(ActionEvent e) {
    try {
     int value = Integer.parseInt(jtaValue.getText());     
     foundedValue = list.indexOf(new Integer(value)); 
     doubleLinkedListAnimation.repaint();
     jtaValue.requestFocus();
    } catch (NumberFormatException e2) {
    }
   }
  });
 }

 class DoubleLinkedListAnimation extends JPanel {
  private static final long serialVersionUID = 1L;
  
  @Override
  protected void paintComponent(Graphics g) {
   super.paintComponent(g);
   int size = 30;
   for (int i = 0; i < list.size(); i++) {
    
    g.setColor(Color.BLACK);
    g.drawRect(2 * size + (i * 4 * size), 2 * size, 2 * size, size);
    g.drawRect(2 * size + (i * 4 * size), 3 * size, 2 * size, size);
    g.drawRect(2 * size + (i * 4 * size), 4 * size, 2 * size, size);
    
    if(i == foundedValue) {
     g.setColor(Color.RED);
    }
    g.drawString(list.get(i) + "", 2 * size + (i * 4 * size) + 4, (int)(2.7 * size));
    if(i == foundedValue) {
     g.setColor(Color.BLACK);
    }
    g.drawString("next", 2 * size + (i * 4 * size) + 4, (int)(3.7 * size));
    g.drawString("previous", 2 * size + (i * 4 * size) + 4, (int)(4.7 * size));
    
    if(i + 1 < list.size()) {
     g.setColor(Color.RED);
     g.drawLine((int)(4 * size) + (i * 4 * size), (int)(3.5 * size), 6 * size + (i * 4 * size), (int)(2.5 * size));
     g.drawLine(6 * size + (i * 4 * size) - 15, (int)(2.5 * size), 6 * size + (i * 4 * size), (int)(2.5 * size));
     g.drawLine(6 * size + (i * 4 * size) - 10, (int)(2.5 * size) + 12, 6 * size + (i * 4 * size), (int)(2.5 * size));
     
     g.drawLine((int)(4 * size) + (i * 4 * size), (int)(2.5 * size), 6 * size + (i * 4 * size), (int)(4.5 * size));
     g.drawLine((int)(4 * size) + (i * 4 * size) + 5, (int)(2.5 * size) + 15, (int)(4 * size) + (i * 4 * size), (int)(2.5 * size));
     g.drawLine((int)(4 * size) + (i * 4 * size) + 15, (int)(2.5 * size) + 5, (int)(4 * size) + (i * 4 * size), (int)(2.5 * size));
    }
   }
   if(list.size() == 0) {
    g.setColor(Color.BLACK);
    g.drawString("head:null", size, size);
    g.drawString("tail:null", size, 2 * size);
   } else {
    g.setColor(Color.RED);
    g.drawLine(size, size, 2 * size, 2 * size);
    g.drawLine(2 * size - 5, 2 * size - 15, 2 * size, 2 * size);
    g.drawLine(2 * size - 15, 2 * size - 5, 2 * size, 2 * size);
    
    g.drawLine(list.size() * 4 * size, 2 * size, list.size() * 4 * size + size, size);
    g.drawLine(list.size() * 4 * size, 2 * size, list.size() * 4 * size + 15, 2 * size - 5);
    g.drawLine(list.size() * 4 * size, 2 * size, list.size() * 4 * size + 5, 2 * size - 15);
    g.setColor(Color.BLACK);
    g.drawString("head", size, size);
    g.drawString("tail", list.size() * 4 * size + size, size);
   }
  }

 }


 public static void main(String[] args) {
  JFrame frame = new JFrame("Exercise11");
  Exercise11 applet = new Exercise11();
  frame.add(applet);
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setSize(900, 300);
  frame.setMinimumSize(new Dimension(frame.getWidth(), frame.getHeight()));
  frame.setLocationRelativeTo(null);
  frame.setVisible(true);
 }
 

}