Doubly linked Implementaions In Java

package LinkedList;

public class DLLNode {
private int data;
DLLNode prev;
DLLNode next;

public DLLNode(int data){
this.data = data;
prev  = null;
next = null;
}

public DLLNode(int data,DLLNode prev,DLLNode next){
this.data = data;
this.prev = prev;
this.next = next;
}

public int getData(){
return data;
}

public void setData(int data){
this.data = data;
}

public DLLNode getPrev(){
return prev;
}

public void setPrev(DLLNode where){
prev = where;
}

public DLLNode getNext(){
return next;
}

public void setNext(DLLNode where){
next = where;
}

}

package LinkedList;

public class DoublyLinkedList {

private DLLNode head;

private DLLNode tail;

private int length;

public DoublyLinkedList() {

head = new DLLNode(90, null, null);

tail = new DLLNode(Integer.MAX_VALUE, head, null);

head.setNext(tail);

length = 0;

}

public int getPosition(int data) {

DLLNode temp = head;

int pos = 0;

while (temp != null) {

if (temp.getData() == data) {

return pos;

}

pos += 1;

temp = temp.getNext();

}

return Integer.MIN_VALUE;

}

public int length() {

return length;

}

public void insert(int data) {

DLLNode newNode = new DLLNode(data, head, head.getNext());

newNode.getNext().setPrev(newNode);

head.setNext(newNode);

length += 1;

}

public void insert(int data, int Position) {

if (Position < 0) {

Position = 0;

}

if (Position > length) {

Position = length;

} else if (Position == 0) {

DLLNode temp = new DLLNode(data);

temp.next = head;

head = temp;

}

else {

DLLNode temp = head;

for (int i = 1; i < Position; i++) {

temp = temp.getNext();

}

DLLNode newNode = new DLLNode(data);

newNode.next = temp.next;

newNode.prev = temp;

newNode.next.prev = newNode;

temp.next = newNode;

length += 1;

}

}

public String toString() {

String result = "[]";

if (length == 0) {

return result;

}

result = "[" + head.getNext().getData();

DLLNode temp = head.getNext().getNext();

while (temp != null) {

result += "," + temp.getData();

temp = temp.getNext();

}

return result + "]";

}

public void insertTail(int newValue) {

DLLNode newNode = new DLLNode(newValue, tail.getPrev(), tail);

newNode.getPrev().setNext(newNode);

tail.setPrev(newNode);

length += 1;

}

public void remove(int position) {

DLLNode temp = head;

for (int i = 1; i < position; i++) {

temp = temp.getNext();

}

temp.getNext().setPrev(temp.getPrev());

temp.getPrev().setNext(temp.getNext());

length -= 1;

}

public int removeTail(){

if(length == 0){

return Integer.MAX_VALUE;

}

DLLNode save = tail.getPrev();

tail.setPrev(save.getPrev());

save.getPrev().setNext(tail);

return save.getData();

}

public static void main(String[] args) {

DoublyLinkedList obj = new DoublyLinkedList();

obj.insert(5);

obj.insert(8);

obj.insert(9);

obj.insert(6);

obj.insert(2);

obj.insert(7);

System.out.println("Before doubly linked list:-"+obj);

System.out.println("position:-" + obj.getPosition(5));

System.out.println("remove tail:-"+obj.removeTail());

System.out.println("After remove from tail doubly linked list becomes:-"+obj);

System.out.println("remove tail:-"+obj.removeTail());

System.out.println("After remove from tail doubly linked list becomes:-"+obj);

/*obj.insert(10, 2);

System.out.println("----------");

System.out.println(obj);*/

System.out.println("head data:-"+obj.head.getData());

System.out.println("head next data:-"+obj.head.getNext().getData());

System.out.println("####################################");

System.out.println("position:-"+obj.getPosition(7));

obj.remove(2);

System.out.println(obj);

}

}