Linked List Implementation - Java Pt. 1

public class MyLinkedList {

private ListNode front; //stores the list node at the front of the LinkedList

//Default constructor for creating an object of MyLinkedList
public MyLinkedList(){

front = null;

}//end default constructor

//determines if the LinkedList is empty
public boolean isEmpty(){

return(front == null);

}//end isEmpty

//adds a ListNode to the beginning of the LinkedList
public void addFirst(Object o){

front = new ListNode(o, front);

}//end addFirst

//adds a ListNode to the end of the LinkedList
public void addLast(Object o){

//checks if the list is empty
if(isEmpty()){

this.addFirst(o);
return;

}//end if

ListNode temp = front;

//loops though LinkedList
while(temp.getNext() != null)
temp = temp.getNext();

temp.setNext(new ListNode(o, null));
temp = null;

}//end addLast

//adds a ListNode to the LinkedList after the first appearance of the specified object
public boolean addAfter(Object target, Object o){

//determines if the LinkedList contains the target
if(isEmpty())
return(false);

ListNode temp = front;

//loops through the LinkedList
while(!(temp == null || temp.getValue().equals(target)))
temp = temp.getNext();

//checks if the temp ListNode is at the end of the LinkedList
if(temp == null)
return(false);

temp.setNext(new ListNode(o, temp.getNext()));
temp = null;
return(true);

}//end addAfter

//removes the specified object from the ListNode (returns false if object isn't in LinkedList)
public boolean remove(Object o){

//checks if the target is in the LinkedList
if(!isEmpty()){

//checks if the first element is the target
if(front.getValue().equals(o))
return(removeFirst());

ListNode temp = front;

//loops through the Linked List
while(!(temp.getNext() == null || temp.getNext().getValue().equals(o)))
temp = temp.getNext();

//checks if the marker isn't at the end of the LinkedList
if(temp.getNext() != null){

ListNode temp2 = temp.getNext();
temp.setNext(temp.getNext().getNext());

temp2.setNext(null);
temp = null;
temp2 = null;

return(true);

}//end if

}//end if

return(false);

}//end remove

//removes the first element in the LinkedList
public boolean removeFirst(){

//checks if the list is empty
if(isEmpty())
return(false);

ListNode temp = front;
front = front.getNext();

temp.setNext(null);
temp = null;
return(true);

}//end removeFirst

//returns the value of the ListNode of a specified location
public Object get(int i){

if(i < 0 || i >= size())
throw new IndexOutOfBoundsException("Index passed in isn't contained in LinkedList.");

ListNode temp = front;

//loops through the LinkedList
for(int x = 0; x < i; x++)
temp = temp.getNext();

Object ret = temp.getValue();
temp = null;

return(ret);

}//end get

//checks if the LinkedList contains the specified object
public boolean contains(Object o){

//checks if the LinkedList is empty
if(!isEmpty()){

ListNode temp = front;

//Loops through the LinkedList
while(temp != null){

//checks if the target is found
if(temp.getValue().equals(o))
return(true);

temp = temp.getNext();

}//end while

}//end if

return(false);

}//end contains

//returns the number of ListNodes in the LinkedList
public int size(){

int i = 0; //stores the number of nodes in the LinkedList

ListNode temp = front;

//loops through the LinkedList
while(temp != null){

temp = temp.getNext();
i++;

}//end while

return(i);

}//end size

//returns a string representation of the LinkedList
public String toString(){

ListNode temp = front;
String ret = "";

//loops through the LinkedList
while(temp!=null){

ret += temp.getValue().toString();
ret += "\n";
temp = temp.getNext();

}//end while

return(ret);

}//end toString

}//end MyLinkedList