Complete the implementation of the methods in the SimpleLinkedList class.

V remove(K key), V remove(int n), V lookup(K key), V remove(), size(), V get(int n), and Object[] toArray()

SimpleLinkedList.java

public class SimpleLinkedList implements List {

private Node head = null;

@Override

public boolean add(K key, V value) {

if (head == null) { // List is empty

Node nn = new Node(key, value);

head = nn;

} else {

Node node = head;

while (node.next != null) {

node = node.next;

}

node.next = new Node(key, value);

}

return true;

}

@Override

public V remove(K key) {

// TODO Auto-generated method stub

return null;

}

@Override

public V remove(int n) {

// TODO Auto-generated method stub

return null;

}

@Override

public V remove() {

// TODO Auto-generated method stub

return null;

}

@Override

public V lookup(K key) {

// TODO Auto-generated method stub

return null;

}

@Override

public int size() {

// TODO Auto-generated method stub

return 0;

}

@Override

public V get(int n) {

// TODO Auto-generated method stub

return null;

}

private class Node {

protected K key;

protected V value;

protected Node next;

Node(K k, V v) {

key = k;

value = v;

next = null;

}

}

@Override

public Object[] toArray() {

return null;

}

@Override

public String toString() {

StringBuilder sb = new StringBuilder();

Node node = head;

while (node != null) {

sb.append("(" + node.key + "," + node.value + ") -- ");

node = node.next;

}

return sb.toString();

}

}

List.java

public interface List { //abstract methods

public abstract boolean add(K key,V value);

public abstract V remove(K key);

public abstract V remove(int n);

public abstract V remove();

public abstract V lookup(K key);

public abstract int size();

public abstract V get(int n);

public abstract Object[] toArray();

public abstract String toString();

}