public class DoublyLinkedList {

private Node header;

private Nodetrailer;

private int size=0;

public DoublyLinkedList()

{

header=new Node(null,null,null);

trailer=new Node(null,header, null);

header.setNext(trailer);

}

public int size()

{

return size;

}

public boolean isEmpty()

{

return size==0;

}

public E first() // to return the first element

{

if (isEmpty())

return null;

return header.getNext().getElement();

}

public E last() // to return the last element

{

if (isEmpty())

return null;

return trailer.getPrev().getElement();

}

public void addBetween(E e, Node predecessor,Nodesuccessor)

{

Employee e1;

Node newest=new Node(e,predecessor, successor);

predecessor.setNext(newest);

successor.setPrev(newest);

size++;

}

public E remove(Node e)

{

if(size==0)

return null;

Node predecessor=e.getPrev();

Node successor=e.getNext();

predecessor.setNext(successor);

successor.setPrev(predecessor);

size--;

return e.getElement();

}

public void addFirst(E e)

{

addBetween(e,header,header.getNext());

}

public void addLast(E e)

{

addBetween(e,trailer.getPrev(),trailer);

}

public E removeFirst()

{

if(isEmpty())

return null;

else

return remove(header.getNext());

}

public E removeLast()

{

if(isEmpty())

return null;

else

return remove(trailer.getPrev());

}

public void displayForward()

{

for (Node t=header.getNext();t!=trailer;t=t.getNext())

System.out.println(t.getElement());

}

public void reverse()

{

Node i=header.getNext();

Node j=trailer.getPrev();

while (i.getNext()!=j && i!=j)

{

E t=i.getElement();

i.setElement(j.getElement());

j.setElement(t);

i=i.getNext();

j=j.getPrev();

}

}

public void displayBackward()

{

for (Node t=trailer.getPrev();t!=header;t=t.getPrev())

System.out.println(t.getElement());

}

public void concat(DoublyLinkedList newList)

{

trailer.getPrev().setNext(newList.header.getNext());

newList.header.getNext().setPrev(trailer.getNext());

trailer=newList.trailer;

}

public static class Node{

private E element;

private Node prev;

private Node next;

public Node(E e,Node p, Node n)

{

element=e;

prev=p;

next=n;

}

public E getElement()

{

return element;

}

public void setElement(E e)

{

element=e;

}

public Node getPrev()

{

return prev;

}

public Node getNext()

{

return next;

}

public void setPrev(Node n)

{

prev=n;

}

public void setNext(Node n)

{

next=n;

}

}

}

Add a new class called Employee that has three private attributes called id (int), name (String) Salary (Double). Add the setter and getter for all the data members. Import the class DoublyLinkedList.java covered in Lab-06 Add a new class called AppTest, create as many objects as you want different amount of Salaries. Using the method public void addBetween(E e, Node predecessor,Node E> successor) add all the objects created recently to the DoublyLinkedList.java in ascending order Add a new class called Employee that has three private attributes called id (int), name (String) Salary (Double). Add the setter and getter for all the data members. Import the class DoublyLinkedList.java covered in Lab-06 Add a new class called AppTest, create as many objects as you want different amount of Salaries. Using the method public void addBetween(E e, Node predecessor,Node E> successor) add all the objects created recently to the DoublyLinkedList.java in ascending order