Chapter 24 Exercise 7, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

24.7 (Animation: linked list) Write a program to animate search, insertion, and deletion in a linked list, as shown in Figure 24.1b. 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.

import javax.swing.*;

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

public class Exercise07 extends JApplet {

 private static final long serialVersionUID = 1L;
 private LinkedListAnimation linkedListAnimation = new LinkedListAnimation();
 private LinkedList<Integer> list = new LinkedList<>();
 private JTextField jtaValue = new JTextField(5);
 private JTextField jtaIndex = new JTextField(5);
 private int foundedValue = -1;
 
 public Exercise07() {
  add(linkedListAnimation, 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);
  add(jPanel, BorderLayout.SOUTH);
  
  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("");      
     }
     linkedListAnimation.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;
     linkedListAnimation.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)); 
     linkedListAnimation.repaint();
     jtaValue.requestFocus();
    } catch (NumberFormatException e2) {
    }
   }
  });
 }

 class LinkedListAnimation 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 * 3 * size), 2 * size, 2 * size, size);
    if(i == foundedValue) {
     g.setColor(Color.RED);
    }
    g.drawString(list.get(i) + "", 2 * size + (i * 3 * size) + 4, (int)(2.7 * size));
    if(i == foundedValue) {
     g.setColor(Color.BLACK);
    }
    g.drawLine(3 * size + (i * 3 * size), 2 * size, 3 * size + (i * 3 * size), 3 * size);
    if(i + 1 < list.size()) {
     g.setColor(Color.RED);
     g.drawLine((int)(3.5 * size) + (i * 3 * size), (int)(2.5 * size), 5 * size + (i * 3 * size), (int)(2.5 * size));
     g.drawLine(5 * size + (i * 3 * size) - 10, (int)(2.5 * size) - 5, 5 * size + (i * 3 * size), (int)(2.5 * size));
     g.drawLine(5 * size + (i * 3 * size) - 10, (int)(2.5 * size) + 5, 5 * size + (i * 3 * 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() * 3 * size - size, 2 * size, list.size() * 3 * size, size);
    g.drawLine(list.size() * 3 * size - size, 2 * size, list.size() * 3 * size - size + 15, 2 * size - 5);
    g.drawLine(list.size() * 3 * size - size, 2 * size, list.size() * 3 * size - size + 5, 2 * size - 15);
    g.setColor(Color.BLACK);
    g.drawString("head", size, size);
    g.drawString("tail", list.size() * 3 * size, size);
   }
  }

 }


 public static void main(String[] args) {
  JFrame frame = new JFrame("Exercise07");
  Exercise07 applet = new Exercise07();
  frame.add(applet);
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setSize(600, 200);
  frame.setMinimumSize(new Dimension(frame.getWidth(), frame.getHeight()));
  frame.setLocationRelativeTo(null);
  frame.setVisible(true);
 }
 

}