JavaSuperPaint/LinkedList.java at master · Androxium/JavaSuperPaint · GitHub

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/*
 * Name: Thomas Cheng
 *
 * Date: May 2, 2018
 *
 * Dsscription: This is the LinkedList<T> class that implements the LinkedListADT<T> class.
 */

classLinkedList<T> implementsLinkedListADT<T> {
privateListNode<T> front = null;
privateintnumberOfNodes = 0;

// Returns true if the linked list has no nodes, or false otherwise.
@Override
publicbooleanisEmpty() {
return (front == null);
 }

// Deletes all of the nodes in the linked list.
// Note: ListNode objects will be automatically garbage collected by JVM.
@Override
publicvoidclear() {
front = null;
numberOfNodes = 0;
 }

// Returns the number of nodes in the linked list
@Override
publicintsize() {
returnnumberOfNodes;
 }

// Adds a node to the front of the linked list.
@Override
publicvoidaddFirst( Telement ) {
front = newListNode<T>( element, front );
numberOfNodes++;
 }

// Returns a reference to the data in the first node, or null if the list is empty.
@Override
publicTpeekFirst() {
if ( isEmpty() )
returnnull;

returnfront.getData();
 }

// Removes a node from the front of the linked list (if there is one).
// Returns a reference to the data in the first node, or null if the list is empty.
@Override
@SuppressWarnings("unchecked")
publicTremoveFirst() {
TtempData;
// if the list is empty
if ( isEmpty() )
returnnull;
// if the list is not empty
tempData = front.getData();
front = front.getNext();
numberOfNodes--;
returntempData;
 }

// Add an element to the end of the linked list
@Override
@SuppressWarnings("unchecked")
publicvoidaddLast( Telement ) {
ListNode<T> node = front;
ListNode<T> back = front;
// if the list is empty
if (front == null){
addFirst( element );
return;
 }
else{
// searches until the end of list
while (node.getNext() != null){
node = node.getNext();
back = node.getNext();
 }
// add the node to the end of the list
back = newListNode( element, null );
node.setNext(back);
 }
numberOfNodes++;
 }

// Remove an element from the end of the list
@Override
@SuppressWarnings("unchecked")
publicTremoveLast(){
ListNode<T> node = front;
ListNode<T> end = front;
Telement;

// list is empty
if (isEmpty())
returnnull;
// list has only 1 element
if (size() == 1){
element = node.getData();
front = null;
numberOfNodes--;
returnelement;
 }
// list has 2+ elements
else{
end = end.getNext();
// searches for the end of the list
while (end.getNext() != null){
node = node.getNext();
end = end.getNext();
 }
// removing the last node from the list
element = end.getData();
node.setNext(null);
numberOfNodes--;
returnelement;
 }
 }


// Returns true if the linked list contains a certain element, or false otherwise.
@Override
@SuppressWarnings("unchecked")
publicbooleancontains( Tkey ) {
ListNode<T> searchNode;
searchNode = front;
while ( ( searchNode != null ) && ( !key.equals( searchNode.getData() ) ) ) {
searchNode = searchNode.getNext();
 }
return ( searchNode != null );
 }

// Return String representation of the linked list.
@Override
@SuppressWarnings("unchecked")
publicStringtoString() {
ListNode<T> node;
StringlinkedList = "FRONT ==> ";

node = front;
while (node != null) {
linkedList += "[ " + node.getData() + " ] ==> ";
node = node.getNext();
 }

returnlinkedList + "NULL";
 }
}