I need help in LinkedList ...

[Usman]

Hello my bros and my sisters .. I am need in this forum .. I hope u guys can help me .. What I need is , I am facing difficulties to relate Class CircularList with ClientNode ...
what I guess is that in class ClientNode , the Button actions has to be be in CircularList by using LinkedList ... and I have four classes in this project , I hope u guys can be able to finish as soon as possible , and I need to implement an Iterator for the linked list.
These are the classes ..

public interface ListInterface
{
    public boolean isEmpty();
    public void clear();
    public void display();
    public void add(Object n, Object a, Object i);
    public void remove(Object o);
    public void search(Object s);
}

public class Node
{
    Object id;  
    Object name;
    Object author;
    Node next;
    Node()
    {
        setNode(null,null,null,null);
    }
    Node(Object name, Object author, Object id, Node next)
    {
        setNode(name,author,id,next);
    }
    void setNode(Object name, Object author, Object id, Node next)
    {
        this.name=name;
        this.author=author;
        this.id=id;
        this.next=next;
    }
    public void setNext(Node next)
    {
        this.next=next;
    }
    public Node getNext()
    {
        return next;
    }
    public void setName(Object name)
    {
        this.name=name;
    }
    Object getName()
    {
        return name;
    }
    public void setAuthor(Object author)
    {
        this.author=author;
    }
    Object getAuthor()
    {
        return author;
    }
    public void setId(Node id)
    {
        this.id=id;
    }
    Object getId()
    {
        return id;
    }
}

import javax.swing.JOptionPane;
public class CircularList implements ListInterface {
    private Node firstNode;
    private Node lastNode;
    private Node head;
    int no_of_nodes;
    
    public CircularList() {
        firstNode = null;
        lastNode = null;
        no_of_nodes = 0;
    }
  
    public boolean isEmpty() {
        if (firstNode == null)
            return true;
        else
            return false;
    }
    public void clear() {
        firstNode = null;
        lastNode = null;
        head = firstNode;
        no_of_nodes = 0;
        JOptionPane.showMessageDialog(null, "The list have been deleted");
    }
  
    public void display() {
        head = firstNode;
        String out = "";
        if (isEmpty())
            out = "List is empty";
        else {
            lastNode.setNext(null);
            while (head != null) {
                out += head.getName() + ", " + head.getAuthor() + "-"
                        + head.getId() + "\n";
                head = head.next;
            }
            lastNode.setNext(firstNode);
        }
        JOptionPane.showMessageDialog(null, out + "");
    }

    public void add(Object n, Object a, Object i) {
        head = firstNode;
        Node newNode = new Node(n, a, i, null);
        if (isEmpty()) {
            firstNode = newNode;
            lastNode = firstNode;
        } else {

            if (no_of_nodes == 1) {
                firstNode.next = newNode;
                lastNode = newNode;
            } else {
                lastNode.setNext(null);
                while (head.next != null) {
                    head = head.next;
                }
                head.next = newNode;
                lastNode = newNode;
                lastNode.setNext(firstNode);
            }
        }
        no_of_nodes++;
    }

    public void remove(Object o) {
        if (isEmpty())
            JOptionPane.showMessageDialog(null,
                    "Can't delete, the list is empty!!");
        else if (no_of_nodes == 1
                && (o + "").equalsIgnoreCase(firstNode.getName() + "")) {
            clear();
            JOptionPane.showMessageDialog(null, "The list is null");
        } else {
            lastNode.setNext(null);
            head = firstNode;
            Node prev = new Node();
            while (head != null) {
                if ((o + "").equalsIgnoreCase(firstNode.getName() + "")) {
                    firstNode = firstNode.next;
                    JOptionPane.showMessageDialog(null, "Data " + o
                            + " have been deleted");
                    no_of_nodes--;
                    break;
                }
                if ((o + "").equalsIgnoreCase(head.getName() + "")) {
                    if (head == lastNode) {
                        lastNode = prev;
                    } else {
                        head = head.next;
                        if (prev == null)
                            prev = head;
                        else
                            prev.next = head;
                    }
                    JOptionPane.showMessageDialog(null, "Data " + o
                            + " have been deleted");
                    no_of_nodes--;
                    break;
                } else {
                    prev = head;
                    head = head.next;
                    if (head == null) {
                        JOptionPane.showMessageDialog(null, "data not found");
                        head = prev;
                        break;
                    }
                }
            }
            lastNode.setNext(firstNode);
        }
    }

    public void search(Object s) {
        if (isEmpty())
            JOptionPane.showMessageDialog(null, "The list is empty!!");
        else {
            lastNode.setNext(null);
            head = firstNode;
            Node prev = new Node();
            while (head != null) {
                if ((s + "").equalsIgnoreCase(head.getName() + "")) {
                    JOptionPane.showMessageDialog(null, head.getName() + ", "
                            + head.getAuthor() + "-" + head.getId() + "\n");
                    break;
                } else {
                    prev = head;
                    head = head.next;
                    if (head == null) {
                        JOptionPane.showMessageDialog(null, "data not found");
                        head = prev;
                        break;
                    }
                }
            }
            lastNode.setNext(firstNode);
        }
    }
}

import java.util.*;
import java.util.List; 
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import static javax.swing.JOptionPane.*;

public class ClientNode extends JFrame 

{ 

    private static final long serialVersionUID = 1L; 
    private JButton addNewBook = new JButton("Add a Book");
    private JButton getSpecificBook = new JButton("Get a Book");
    private JButton getAllBooks = new JButton("Get all Books");
    private JButton removeOneBook = new JButton("Remove a Book");
    private JButton removeAllBooks = new JButton("Remove all Books");
    private JButton checkList = new JButton("Check List");

    private JPanel buttonsPanel = null; 
    private JPanel statusPanel = null; 
    private List exampleLinkedList = null; 
    private DefaultListModel model; 
    JList list; 
    CircularList listt = new CircularList(); 

    public ClientNode() { 
        exampleLinkedList = new LinkedList(); 
        exampleLinkedList.clear(); 
        exampleLinkedList.add("Linked List Example"); 

        model = new DefaultListModel(); 
        list = new JList(model); 
        
        buttonsPanel = new JPanel(); 
        statusPanel = new JPanel(); 

        JScrollPane scrollPane = new JScrollPane(list); 

        getContentPane().add(scrollPane, BorderLayout.SOUTH); 
        // Add Them to a panel 
        buttonsPanel.add(addNewBook); 
        buttonsPanel.add(getSpecificBook); 
        buttonsPanel.add(getAllBooks); 
        buttonsPanel.add(removeOneBook); 
        buttonsPanel.add(removeAllBooks); 
        buttonsPanel.add(checkList); 

        statusPanel.add(scrollPane); 

        // Add elements to the frame 
        add(buttonsPanel, BorderLayout.NORTH); 
        add(statusPanel, BorderLayout.SOUTH); 

        addNewBook.addActionListener(new ActionListener() { 

            public void actionPerformed(ActionEvent e) { 

                String n = JOptionPane.showInputDialog("Enter book name : "); 
                String a = JOptionPane.showInputDialog("Enter author name : "); 
                String i = JOptionPane.showInputDialog("Enter book ID : "); 
                listt.add(n, a, i); 
                String result = "Book : " + " " + n + "  Author : " + a 
                        + "  ID: " + i; 

                exampleLinkedList.add(result); 

                model.add(list.getModel().getSize(), result); 

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

            public void actionPerformed(ActionEvent e) { 
                try { 

                    if (!exampleLinkedList.isEmpty()) { 

                        // addLogMessage("\nGet Specific Item Example"); 
                        String result = ""; 
                        int max = exampleLinkedList.size() - 1; 

                        result = JOptionPane 
                                .showInputDialog("Enter number between 0 and " 
                                        + max); 

                        Object x = model.get(Integer.parseInt(result)); 
                        JOptionPane.showMessageDialog(null, x); 
                        System.out.println(x); 
                        String y = x.toString(); 

                        JTextPane text = new JTextPane(); 
                        text.setText(y); 
                        // Font f = new Font("verdana", Font.BOLD + Font.ITALIC, 
                        // 16); 
                        // O setJTextPaneFont(text, f, Color.blue); 

                        list.setForeground(new Color( 
                                (int) (Math.random() * 222), (int) (Math 
                                        .random() * 205), 
                                (int) (Math.random() * 213))); 
                        // list.setFont(f); 

                    } else { 
                        JOptionPane 
                                .showMessageDialog(null, 
                                        "no item to return ,please add at least one item"); 
                    } 
                } catch (Exception ex) { 
                    JOptionPane.showMessageDialog(null, "no such item index"); 
                } 

            } 
        }); 

        getAllBooks.addActionListener(new ActionListener() { 
            ArrayList<String> items = new ArrayList<String>(); 
            public void actionPerformed(ActionEvent e) { 

                if (!exampleLinkedList.isEmpty()) { 

                    for (int i = 0; i < model.getSize(); i++) { 

                        System.out.println(model.get(i)); 
                        items.add((String) model.get(i)); 
                    } 
                    JOptionPane.showMessageDialog(null, items.toArray()); 
                } 

                else { 
                    JOptionPane.showMessageDialog(null, 
                            "no items to return ,please add at least one item"); 
                } 
            } 
        }); 

        removeOneBook.addActionListener(new ActionListener() { 

            public void actionPerformed(ActionEvent e) { 
                try { 

                    if (!exampleLinkedList.isEmpty()) { 

                        // addLogMessage("\nRemove One Item Example"); 
                        String result = ""; 
                        int max = exampleLinkedList.size() - 1; 

                        result = JOptionPane 
                                .showInputDialog("Enter number between 0 and " 
                                        + max); 

                        model.remove(Integer.parseInt(result)); 
                    } else { 

                        JOptionPane 
                                .showMessageDialog(null, 
                                        "no items to remove ,please add at least one item"); 

                    } 
                } catch (Exception exe) { 
                    JOptionPane.showMessageDialog(null, 
                            "no such item " + exe.getMessage()); 
                } 
            } 
        }); 

        removeAllBooks.addActionListener(new ActionListener() { 

            public void actionPerformed(ActionEvent e) { 

                if (!exampleLinkedList.isEmpty()) { 

                    // addLogMessage("\nRemove All Items Example"); 
                    // exampleLinkedList.clear(); 
                    model.clear(); 
                    // addLogMessage("List has been cleared"); 
                } else { 
                    // you can make it as exception for the array size 
                    JOptionPane.showMessageDialog(null, 
                            "no items to remove ,please add at least one item"); 
                } 
            } 
        }); 

        checkList.addActionListener(new ActionListener() { 

            public void actionPerformed(ActionEvent e) { 
                if (exampleLinkedList.isEmpty()) { 
                    // addLogMessage("List is empty"); 
                    JOptionPane.showMessageDialog(null, 
                            "no items to check ,please add at least one item"); 
                } else { 
                    JOptionPane.showMessageDialog(null, "List is not empty"); 
                } 
            } 
        }); 

    } 
    public static void main(String args[]) { 
        ClientNode theApplication = new ClientNode(); 

        theApplication.setDefaultCloseOperation(EXIT_ON_CLOSE); 
        theApplication.setSize(500, 500); 
        theApplication.pack(); 
        theApplication.setVisible(true); 

    } 
}

[Usman]

I need ur help guys .. as soon as possible .. the submitting after 2 hours

[Mjall]

I don't understand the problem,
You're buttons are not working or you have not created an Iterator?

Mjall

[Usman]

my Buttons are working .. but I have to call the method from CircularList to ClientNode
and create an Iterator