Linked List Implementation Java

Download Source Code LinkedList.java and Node.java



LinkedList.java

	package data.structures.LinkedList;
	/**
	*
	* @author jasleen
	* @param <T>
	*/
	public class LinkedList <T>{
	Node<T> head=null;
	private Node<T> current;
	public void remove(T t)
	{
	//System.out.println(t);
	Node currentTraversing=head();
	if(currentTraversing.key()==t)
	{
	if(current==currentTraversing)
	current=null;
	head(currentTraversing.next());
	currentTraversing=null;
	return;
	}
	while(currentTraversing.next()!=null &&!currentTraversing.next().key().equals(t))
	{
	currentTraversing=currentTraversing.next();
	}
	if(currentTraversing!=null)
	{
	Node itemToBeremoved=currentTraversing.next();
	if(itemToBeremoved==null)
	{
	System.out.println("Key not found. Sorry!!!");
	}
	if(itemToBeremoved==current)
	current=currentTraversing;
	if(itemToBeremoved!=null&&itemToBeremoved.next()!=null)
	currentTraversing.next(itemToBeremoved.next());
	else
	currentTraversing.next(null);
	}
	}
	public void remove()
	{
	Node currentTraversing=head();
	if(currentTraversing!=null)
	{
	while(currentTraversing!=null&& currentTraversing.next()!=current)
	{
	currentTraversing=currentTraversing.next();
	}
	System.out.println(currentTraversing.key());
	currentTraversing.next(null);
	current=currentTraversing;
	}
	else
	{
	System.out.println("No Item to remove");
	}
	}
	public void setCurrent(Node<T> current) {
	this.current = current;
	}
	public void add(T t)
	{
	if(head()!=null)
	{
	current.next(new Node<>(t));
	current=current.next();
	}
	else
	{
	head=new Node<>(t);
	current=head;
	}
	}
	public void addAtHead(T t)
	{
	if(head()!=null)
	{
	Node oldHead=head();
	//Setting head to new node
	Node newHead=new Node<>(t);
	head(newHead);
	//Setting the next element of new head to old head
	head().next(oldHead);
	}
	else
	{
	head=new Node<>(t);
	}
	}
	public Node<T> head()
	{
	return head;
	}
	public void head(Node<T> t)
	{
	this.head=t;
	}
	@Override
	public String toString() {
	StringBuilder builder=new StringBuilder();
	builder.append("[");
	builder.append("\t");
	Node currentTraversing=head();
	while(currentTraversing!=null)
	{
	builder.append(currentTraversing.key().toString());
	builder.append("\t");
	currentTraversing=currentTraversing.next();
	}
	builder.append("]");
	return builder.toString();
	}
	public void removeHead() {
	Node oldHead=head();
	head(oldHead.next());
	oldHead=null;
	}
	}

Node.java

/*
	* To change this license header, choose License Headers in Project Properties.
	* To change this template file, choose Tools | Templates
	* and open the template in the editor.
	*/
	package data.structures.LinkedList;
	/**
	*
	* @author jasleen
	* @param <T>
	*/
	public class Node<T> {
	private Node next,previous;
	private T key;
	public Node(T key) {
	this.previous = null;
	this.next = null;
	this.key=key;
	}
	public T key() {
	return key;
	}
	public void key(T key) {
	this.key=key;
	}
	void next(Node node)
	{
	this.next=node;
	}
	public Node next()
	{
	return next;
	}
	public void previous(Node node)
	{
	this.previous=node;
	}
	public Node previous()
	{
	return previous;
	}
	@Override
	public String toString() {
	return key.toString(); //To change body of generated methods, choose Tools | Templates.
	}
	}