package class5_3_QueueInterface;

import java.util.LinkedList;
import java.util.List;

/* Unchanged from class 5_2 code */


// TODO: Untested code!
public class LinkedQueue<E> implements Queue<E> {

    private List<E> list = new LinkedList<E>();

    @Override
    public E poll() {
        E result;
        if(list.size() > 0) {
            result = list.remove(list.size()-1);
        } else {
            result = null;
        }
        return result;
    }

    @Override
    public boolean offer(E e) {
        list.add(0,e);
        return true;
    }

    @Override
    public E peek() {
        E result;
        if(list.size() > 0) {
            result = list.get(list.size()-1);
        } else {
            result = null;
        }
        return result;
    }

    @Override
    public boolean isEmpty() {
        return list.size() == 0;
    }
}