WAP to Implemen The All Function Of Doubly Linked lIst

import java.util.Iterator;




public class DoublyLInkedList {


Node head = null;
Node tail = null;




public Node getHead() {
return head;
}
public void setHead(Node head) {
this.head = head;
}
public Node getTail() {
return tail;
}
public void setTail(Node tail) {
this.tail = tail;
}

private Node createNode(T data) {
Node node = new Node();
node.setData(data);
node.setNext(null);
node.setPrevious(null);
return node;

}

public void insertAtHead(Node node) {
if (getHead() == null) {
System.out.println("Creating first Head " + node.getData());
setHead(node);
setTail(node);
}
else {
node.setPrevious(null);
node.setNext(getHead());
getHead().setPrevious(node);
setHead(node);
System.out.println("Inserting at head " + node.getData());
}

}

public Node insertAtHead(T data) {
if (data == null)
return null;
//if head is null first node
Node node = createNode(data);
insertAtHead(node);
return node;
}

private Node findNode(T data) {
Node tmp = head;
while(tmp != null) {
//System.out.println("findNode :: Comparing " + tmp.getData() + " with " + data);
if (tmp.getData().equals(data))
return tmp;
tmp = tmp.getNext();
}
return null;
}

public void remove(T data) {
Node node = findNode(data);
remove(node);
}

public void remove(Node node) {
if (node == null)
return;
//1 node in list
if (node.getPrevious() == null &&
node.getNext() == null) {
setHead(null);
setTail(null);
return;
}
//head node
if (node.getPrevious() == null &&
node.getNext() != null) {
//head node
setHead(node.getNext());
node.setNext(null);
return;
}
// tail node
if (node.getNext() == null &&
node.getPrevious() != null) {
//tail node
setTail(node.getPrevious());
node.getPrevious().setNext(null);
return;
}
// center node
System.out.println("Removing center node from list with value [ " + node.getData() + "] whose previous = [" + node.getPrevious().getData() + "] and next = [" + node.getNext().getData() + "]");
node.getPrevious().setNext(node.getNext());
node.getNext().setPrevious(node.getPrevious());
node.setNext(null); node.setPrevious(null);
}


private class ListIterator implements java.util.Iterator {
Node currentNode;

public ListIterator() {
currentNode = getHead();

}

public boolean hasNext() {
// TODO Auto-generated method stub
if (currentNode != null)
{
// System.out.println("Current node is not null and is pointing to " + currentNode.getData());
return true;
}
else
return false;
}

public T next() {
// TODO Auto-generated method stub
//System.out.println("Current node = " + currentNode.getData() );
T data = (T) currentNode.getData();
currentNode = currentNode.getNext();
return data;
}

public void remove() {
// TODO Auto-generated method stub
DoublyLInkedList.this.remove(currentNode);

}
}

public Iterator iterator() {
return new ListIterator();

}

public static void main(String[] args) {
System.out.println("Test");
DoublyLInkedList dList = new DoublyLInkedList();
String str1 = new String("1");
String str2 = new String("2");
String str3 = new String("3");
dList.insertAtHead(str1);
dList.insertAtHead(str2);
dList.insertAtHead(str3);
Iterator it = dList.iterator();
while (it.hasNext()) {
System.out.println(it.next());

}
System.out.println("Tail Node = " + dList.getTail().getData());
dList.remove(str1);
Iterator it1 = dList.iterator();
while (it1.hasNext()) {
System.out.println(it1.next());

}
System.out.println("Tail Node = " + dList.getTail().getData());

}

}


Sourse https://github.com/inders/datastructure-repo/blob/master/LRUCache/src/DoublyLInkedList.java