Phone Directory program

Hi

I have project in Data Structures

this is the question

1.Phone Directory
Design a phone directory that will be able to store names of teachers and their office phone numbers. Your system should be able to "quickly" insert or search the entries.


I want ues insert method

so the user can add teacher name, Id,Phone number and teacher room in to current list

how can I do this

I tries and I have add insertlist method BUT it have some errors .. could you please hepl my to find what are the errors ....
those are the cods after adding the method // ??

and this is 4 class for the program I have used Doubley linked list

main class

 //-------------------------------------------------------------------------------------Backages
import java.util.*;
import java.util.Scanner;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

//--------------------------------------------------------------------------------------Class Main
public class Main extends JFrame 
{
         final Users theUser = new Users();
          
//------------------------------------------------------------------------------------1--Method main  
public static void main(String[] args)
  { 
        new Main().setVisible(true);//call method Main   
  }//end public static void main

//-----------------------------------------------------------------------------------2--Mathod Main
  public Main() 
  {
         theUser.Users();
         //------------------
         setTitle("Phone Directory");
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//---------------------------------------------------------------------------Date-Photo-size-color
         Date da = new Date();
         Container contentPane = getContentPane();
         contentPane.setLayout(new BorderLayout());
         contentPane.setBackground(Color.green);
         setSize(300,300);
         //-------------------
         JLabel time = new JLabel("          Today is : " +da);
       getContentPane().add(time);
         //----------------
        setResizable(false);		
         setLocationRelativeTo(null); 	
         String imgStr1 = "c://EQLS.png";
         ImageIcon image = new ImageIcon(imgStr1);	 
         JLabel label1 = new JLabel(" ", image, JLabel.CENTER);
         getContentPane().add(label1);
         validate();	
         setVisible(true); 
//-----------------------------------------------------------------------------------------Button1
    JButton button1 = new JButton("*~...~*  Welcome *~...~*");
    
    button1.addActionListener(new ActionListener() {   public void actionPerformed(ActionEvent e) 
      {
          JOptionPane.showMessageDialog((Component) e.getSource(), "\n\nThe main idea behind my system is\n\n\n to make the search for teacher information easier using a computer system.\n\n");
        }
    });//end button1
    
//-----------------------------------------------------------------------------------------Button2
    JButton button2 = new JButton("Main User Access: Phone Directory");
    button2.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e)
      { 
         String Option1 = JOptionPane.showInputDialog(null,"Please Enter The Number of Choice !? \n1) View list ROOM\n2) SEARCH THE DATA OFTEACHER\n3) Remove DATA OF TEACHER list\n4) Delete\n5) Return\n6) Exit\n", "Phone Directory Options", JOptionPane.INFORMATION_MESSAGE);
         int ConvOption1 = Integer.parseInt(Option1);
         theUser.mainUser(ConvOption1,Option1);//go to main User method
      }//end method public void actionListener       String Option1 = JOptionPane.showInputDialog(
    });//end button2
    
//-----------------------------------------------------------------------------------------Button3		 
    JButton button3= new JButton("Exit");
    button3.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e)
      {
        int result = JOptionPane.showConfirmDialog((Component) e.getSource(),"Close Phone Directory SYSTEM");
        if (result == JOptionPane.YES_OPTION)
        {System.exit(0);} 
      }
    });//end button3
//------------------------------------------------------------------------------------------
  //  setLayout(new FlowLayout(FlowLayout.CENTER));
    setLayout(new GridLayout(8,4));
    getContentPane().add(button1);
    
   getContentPane().add(button2);
    
    getContentPane().add(button3);
    
  }//end public method Main
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
}//end class Main

users class

import javax.swing.JFrame; 
import java.util.Scanner;
import javax.swing.JOptionPane;

class Users
{ 
     linkList theList = new linkList();
     Scanner input = new Scanner(System.in);
      
       int a = 0; 
       int b = 0;       
       int key,r;
       Link v,d, f;
       
public void Users()
{    

JOptionPane.showMessageDialog (null, "   *~...~*  WELCOME *~...~*\n\n  PHONE DIRECTORY SYSTEM\n\n    For Login Please Click Ok\n\n", " {ELECTRONIC SYSTEM OF PHONE DIRECTORY]", JOptionPane.INFORMATION_MESSAGE);
 JFrame frame = new JFrame();

        int SENTINEL = 123; //password number
        String str;  //password number which the user will Enter it
        int password = 0;
        int counter = 5;
        
              
while (counter != 0 && password != SENTINEL)
       {     
        str = JOptionPane.showInputDialog("Enter Password");
       
        password = Integer.parseInt(str);
          
        if(password == SENTINEL)
        {
            JOptionPane.showMessageDialog(null, "CORRECT");
            System.out.println("\n\t*~...~* The Messages of PHONE DIRECTORY SYSTEM *~...~*\n\n-------------------------------------------------------------------------- \n");        
        }
        else if(password!=SENTINEL)
        {
             JOptionPane.showMessageDialog(null, "Wrong try again");
        }
        counter = counter-1;
       
        if (counter == 0)
        {
            JOptionPane.showMessageDialog(null, "Acces Denied!!! \nPlease contact Helpdesk");      
            System.exit(0);
        }
       }
           String backupDir="" ;
       
                theList.insertFirst(16, "08120014", "Ms. Fahmeeda Aziz","043258088");
                theList.insertFirst(15, "08120014", "Dr. Farhana Shaheen ","043258088");
                theList.insertFirst(14, "08120014", "Dr. Fatima Al-Zwaihri ", "043258088");
                theList.insertFirst(13, "08120014", "Dr. Tahani Sindi    ", "043258088"); 
                theList.insertFirst(12, "08120014", "Dr. Nagla Osman     ", "043935024"); 
                theList.insertFirst(11, "08120014", "Ms. Atiya Azmi      ", "043258088"); 
                theList.insertFirst(10, "08120014", "Ms. Aisha Al-Johani   ", "043258088");
                theList.insertFirst(9, "08120014", "Ms. Siti Haryani Mohd ", "043935024"); 
                theList.insertFirst(8,"08120014", "Ms.Humera Ghani     ", "043258088");
                theList.insertFirst(7, "08120014", "Ms. Salma Sadiqha    ", "043258088");
                theList.insertFirst(6, "08120014", "Ms. Azra Sultana     ", "043935024"); 
                theList.insertFirst(5, "08120014", "Ms. Ruchi Tuli     ", "043258088");
                theList.insertFirst(4, "08120014", "Ms. Fozia Noor   ", "043258088");
                theList.insertFirst(3, "08120014", "Ms. Kajal nusratullah  ", "043258088");
                theList.insertFirst(2, "08120014", "Ms.Anusuyah Subbarao  ", "043935024");
                theList.insertFirst(1, "08120014", "Ms. Aizal Yusrina ", "043258088");
}

public void mainUser(int ConvOption1,String Option1)
{
while(ConvOption1!=6)
    {
       switch (ConvOption1) // 5 cases
       {
       case 1: {
               theList.displayList();
               System.out.println("---------------------------------------------------------------------------\n");
              }
       break;
       
       case 2: {
       	
       	//  Option1 = JOptionPane.showInputDialog("Enter how MANY TEACHERS U WANT TO FIND");
      //        a = Integer.parseInt(Option1);
                    
    System.out.println("Enter how MANY TEACHERS U WANT TO FIND");
            a=input.nextInt();
               
              //theList. display1() ;
               for(int j=1;j<=a;j++)
               {
               	
           //    	Option1 = JOptionPane.showInputDialog("\nEnter Number of Teacher Room   ÏÏ "+j+" ÏÏ ");
           //     b = Integer.parseInt(Option1);
                  
             System.out.println("\nEnter Number of Teacher Room   ÏÏ "+j+" ÏÏ ");
               b=input.nextInt();
                
               f = theList.find( B)/>/>; 
                        // find item
               if( f != null)
               {
               
            System.out.println("\nTEACHER NAME IS: "+f.Teacher_Name+"\nTEACHER ID: "+f.teacher_ID+"\nPHONE NUMBER IS: "+f.Phone_number);
               
             //  JOptionPane.showMessageDialog(null,"\nTEACHER NAME IS: "+f.Items+"\nTEACHER ID: "+f.qui+"\nPHONE NUMBER IS: "+f.price);
                 
                // System.out.println("\nQuintity of "+f.Items+" Now is "+e);
                 
                 }
               else
               {
               System.out.println("we did FOUND "+f.Teacher_Name);  
                } 
                }
               
              // System.out.println("\n ÒÒ price ="+t);
                
              System.out.println("---------------------------------------------------------------------------\n");
            }
      break;
      
      case 3: {
          
          System.out.println("Enter THE ROOM NUMBER OF TEACHER  ");
          int key=input.nextInt();
          Link i = theList.delete(key);        // delete item
          if( i != null )
          {
          
           System.out.println("Deleted NUMBER OF ROOM : "+  i.Room_Number+"\n");
           System.out.println("Delet the ID :  "+i.teacher_ID +"\n");
           System.out.println("Delet the Name Of TEACHER : "+ i.Teacher_Name+"\n" );
           System.out.println("Delet the PHONE NUMBER :  "+i.Phone_number+"\n");
          
          
          System.out.println("SUCCESSFUL DELET");
          } 
          else
          {
          
          System.out.println("Can't delete ");
          
          System.out.println("the data still in list "+i);
          }
          System.out.print("---------------------------------------------------------------------------\n");
             } 
          break;
       
       case 4: {
              theList.display2();
              System.out.println("Enter ROOM NUMBER:>");
              key= input.nextInt();
              Link i = theList.delete(key);  
              System.out.print("---------------------------------------------------------------------------");
              
              System.out.println("\nlist after EDIT:>");
              theList.display2();
              System.out.println("---------------------------------------------------------------------------\n");
             }
        break;
          
                 case 5: {
              theList.display2();
              System.out.println("Enter New Teacher  Room NUMBER:>");
              key= input.nextInt();
              Link i =  theList.insertLast(key);  
              System.out.print("---------------------------------------------------------------------------");
              
              System.out.println("\nlist after EDIT:>");
              theList.display2();
              System.out.println("---------------------------------------------------------------------------\n");
             }
        break;
   }//end switch
   
    if(ConvOption1>6)
    {
    
     JOptionPane.showMessageDialog(null, "YOUAR INPUT NUMBER NOT IN THE LIST\n              PLEASE, TRY AGAIN");   	
    }
     Option1 = JOptionPane.showInputDialog("\n1-Show List of TEACHERS\n2-SEARCH \n3-Remove \n4-Borrow\n5-Return\n6-Exit");
     ConvOption1 = Integer.parseInt(Option1);
    }//end while
   }
}//end mainUser method

Link class

 class Link 
  { 
    public int Room_Number; 
    public String teacher_ID; 
    public String Teacher_Name; 
    public String Phone_number; // data item 
    public Link next; // next link in list 

    // ------------------------------------------------------------- 

    public Link(int a, String b, String teacher, String Phone) // constructor 
    { 
        Room_Number = a; 
        teacher_ID = b; // constructor 
        Teacher_Name = teacher; 
        Phone_number = Phone; 

    } // set to null) 
        // ------------------------------------------------------------- 

    public void displayLink1() 
    // display ourself 
    { 

        System.out.println("\t" + Teacher_Name + "\t\t{" + Room_Number + "}"); 
        System.out.println(""); 
    } 


    public void displayLink2() 
    // display ourself 
    { 
        System.out.print("\t" + Room_Number); 
        System.out.print("\t" + teacher_ID); 
        System.out.print("\t" + Teacher_Name); 
        System.out.println("\t\t{" + Phone_number + "}"); 
    }
} 

linkList class

class linkList
 { 
    private Link first; // ref to first link on list 

    // ------------------------------------------------------------- 
    public linkList() // constructor 
    { 
        first = null; // no links on list yet 
    } 

    // ------------------------------------------------------------- 
    public boolean isEmpty() // true if list is empty 
    { 
        return (first == null); 
    } 
    // ------------------------------------------------------------- 
    // insert at start of list 
        public String insertFirst(int a, String SD, String teacher, String Phone) { // make 
                                                                        // new 
                                                                        // link 
        Link newLink = new Link(a, SD, teacher, Phone); 
        newLink.next = first; // newLink --> old first 
        first = newLink; // first --> newLink 
        return first.Room_Number + "  " + first.teacher_ID + "  " + first.Teacher_Name + "{" + first.Phone_number + "}"; 
    } 

    // ------------------------------------------------------------- 
    public Link find(int key) // find link with given key 
    { // (assumes non-empty list) 
        Link current = first; // start at 'first' 
        while (current.Room_Number != key) // while no match, 
        { 
            if (current.next == null) // if end of list, 
                return null; // didn't find it 
            else 
                // not end of list, 
                current = current.next; // go to next link 
        } 
        return current; // found it 
    } 

    // ///////////////////////////////////// 
    public Link delete(int key) // delete link with given key 
    { // (assumes non-empty list) 
        Link current = first; // search for link 
        Link previous = first; 
        while (current.Room_Number != key) { 
            if (current.next == null) 
                return null; // didn't find it 
            else { 
                previous = current; // go to next link 
                current = current.next; 
            } 
        } // found it 
        if (current == first) // if first link, 
            first = first.next; // change first 
        else 
            // otherwise, 
            previous.next = current.next; // bypass it 
        return current; 
    } 


    // -------------------------------------------------------------
     
 public void insertLast( int key)    
      {
      Link newLink = new Link(key); // make new link
      if( isEmpty() )                // if empty list,
         first = newLink;            // first --> newLink
      else
         {
         last.next = newLink;        // old last --> newLink
         newLink.previous = last;    // old last <-- newLink
         }
         last = newLink;                // newLink <-- last
      }

    // ------------------------------------------------------------- 
    
    public void displayList() { 
        System.out.println("\t\t\n\n                        *~...~*  Welcome *~...~*\n\n "); 
        System.out.print("\n\n\t\t               The Menue  \n\n"); 
        System.out.println("\n\t :: NAME OF TEACHERS ::\t\t:: NUMBER OF ROOM ::"); 
        System.out.println(""); 
        Link current = first; // start at beginning of list 
        while (current != null) // until end of list, 
        { 
            current.displayLink1(); // print data 
            current = current.next; 
            // move to next link 
        } 
        System.out.println(""); 
    } 

    public void display2() { 
        System.out.print("\t\t        *~...~*  The Menue *~...~*  \n\n"); 
        System.out.println("\n\tR.N.    ID              TEACHER NAME \t                PHONE NUMBER\n "); 
        Link current = first; // start at beginning of list 
        while (current != null) // until end of list, 
        { 
            current.displayLink2(); // print data 
            current = current.next; 
            // move to next link 
        } 
        System.out.println(""); 
    } 
    // ------------------------------------------------------------- 
} // end class LinkList