Hello, I need some help modifying some java code here is the modification . Its a data structure that holds student grades:

insert (sorted)

Add a getKey mehod to the StudentListings class

search list for insertion point: while (not at end of list && key < newNodesKey)

Insert a newNode and the deepCopy at insertion point

fetch and delete (sorted speed-up)

Same search as unsorted, but should return an error when the node is not in the list or we get to a node that is greater than given key (speed-up).

And here is my code:

package database;

import javax.swing.JOptionPane;

public class StudentListing

{//start StudentListing class

private String name;

private String idnumber;

private String gpa;

public StudentListing(String n, String id, String grd)

{

name = n;

idnumber = id;

gpa = grd;

}

StudentListing()

{

}

public String toString( )

{

return("Name: " + name +

" ID number: " + idnumber +

" GPA: " + gpa + " ");

}

public StudentListing deepCopy()

{

StudentListing clone = new StudentListing(name, idnumber, gpa);

return clone;

}

public int compareTo(String targetKey)

{

return(name.compareTo(targetKey));

}

public void setIdnum(String id)

{

idnumber = id;// coded to demonstrate encapsulation

}

public void inputNode()

{//start inputNode

name = JOptionPane.showInputDialog("Enter a name");

idnumber = JOptionPane.showInputDialog("Enter the ID Number");

gpa = JOptionPane.showInputDialog("Enter the GPA");

}//end inputNode

}//end studentListing class

****************************************************************

package database;

import javax.swing.*;

public class Main

{//START CLASS

public static void main(String[] args)

{//START MAIN

UOAUtilities s = new UOAUtilities();

StudentListing f = new StudentListing();

int choice;

String name;

StudentListing c = new StudentListing();

do

{//START DO

choice = Integer.parseInt(JOptionPane.showInputDialog(

"1 to insert a new student's information "+

"2 to fetch and output a student's information "+

"3 to delete a student's information "+

"4 to update a student's information "+

"5 to output all the student information in sorted order "+

"6 to quit the program"));

if(choice < 1 || choice > 6)

{//if out of range

JOptionPane.showMessageDialog(null, "Number entered is out of range.");

}

switch(choice)

{ //start switch statement

case 1: f.inputNode();

s.insert(f);

break;

case 2: JOptionPane.showMessageDialog(null, s.fetch(name = JOptionPane.showInputDialog("search for name:")));

break;

case 3: JOptionPane.showMessageDialog(null, s.delete(name = JOptionPane.showInputDialog("student to delete")));

break;

case 4: c.inputNode();

s.update(JOptionPane.showInputDialog(null, "student name to update:"), c);

break;

case 5: s.showAll();

break;

}//end switch statement

}//END DO

while(choice != 6);//quit the program

}//END MAIN

}//END CLASS

****************************************

package database;

public class SinglyLinkedList

{

private Node h; // list header

public SinglyLinkedList()

{ h = new Node(); // dummy node

h.l = null;

h.next = null;

}

public boolean insert(StudentListing newListing)

{ Node n = new Node();

if(n == null) // out of memory

return false;

else

{ n.next = h.next;

h.next = n;

n.l = newListing.deepCopy();

return true;

}

}

public StudentListing fetch(String targetKey)

{ Node p = h.next;

while (p != null && !(p.l.compareTo(targetKey) == 0))

{ p = p.next;

}

if(p != null)

return p.l.deepCopy();

else

return null;

}

public boolean delete(String targetKey)

{ Node q = h;

Node p = h.next;

while (p != null && !(p.l.compareTo(targetKey) == 0))

{ q = p;

p = p.next;

}

if(p != null)

{ q.next = p.next;

return true;

}

else

return false;

}

public boolean update(String targetKey, StudentListing newListing)

{ if(delete(targetKey) == false)

return false;

else if(insert(newListing) == false)

return false;

return true;

}

public void showAll()

{ Node p = h.next;

while (p != null) //continue to traverse the list

{ System.out.println(p.l.toString( ));

p = p.next;

}

}

public class Node

{ private StudentListing l;

private Node next;

public Node()

{

}

}// end of inner class Node

}//end SinglyLinkedList outer class

**********************************

package database;

import javax.swing.*;

public class UOAUtilities

{//start UOAUtilities class

private int next;

private int size;

private StudentListing[] data;

public UOAUtilities()

{//Start of constructor

next = 0;

size = 100;

data = new StudentListing[size];

}//end of constructor

public UOAUtilities (int s)

{//Start of constructor

next = 0;

data = new StudentListing[s];

size = s;

}//end of constructor

public boolean insert(StudentListing newStudentListing)

{ //insert method starts

if(next >= size) // if the structure is full

return false;

data[next]= newStudentListing.deepCopy( ); // store a deep copy of the clients node

if(data[next] == null)

return false;

next = next + 1; // prepare for the next insert

return true;

}// end of insert method

public StudentListing fetch(String targetKey)

{ //start of fetch method

StudentListing node;

StudentListing temp;

// access the node using a sequential search

int i = 0;

while ( i < next && !(data[i].compareTo(targetKey) == 0))

{

i++;

}

if(i == next) // if node not found

{JOptionPane.showMessageDialog(null, "Node was not found");

return null;

}

//deep copy the node's information into the client's node

node = data[i].deepCopy( );

// move the node up one position in the array, unless it is the first node

if(i != 0) // bubble-up accessed node

{

temp = data[i-1];

data[i-1] = data[i];

data[i] = temp;

}

return node;

} // end of fetch method

public boolean delete(String targetKey)

{// access the node using a sequential search

int i = 0;

while (i < next && !(data[i].compareTo(targetKey) == 0))

{

i++;

}

if(i == next) // if node not found

{

JOptionPane.showMessageDialog(null, "The node could not be delteted becasue it was not found");

}

//move the last node into the deleted node's position

data[ i] = data[ next -1];

data[next-1] = null;

next = next - 1;

return true; // if node found and deleted

}//end of the delete method

public boolean update(String targetKey, StudentListing StudentListings)

{//start update method

if(delete(targetKey) == false)

{JOptionPane.showMessageDialog(null, "Node not in the structure, update was unsucessful");

return false;

}

else if( insert(StudentListings) == false)

{

JOptionPane.showMessageDialog(null, "Insufficient memory update was unsucessful");

return false;

}

else

{

JOptionPane.showMessageDialog(null, "The student was updated succesffuly");

return true; // node found and updated

}

}// end of update method

public void showAll( )

{// Start showAll method

for(int i = 0; i< next; i++)

System.out.println( data[i].toString());//print out all data

}// end showAll method

}//end of class UOAUtilities

Any questions please let me know any help is appreciated!