package stack;

import exceptions.EmptyStackException;
import stack.utility.Node;

/**
 * Created with MONSTER.
 * User: xgiovio
 * Date: 05/03/14
 * Time: 0.12
 */
//Copyright (c) 2003 Brown University, Providence, RI
//Additional modifications and methods by xgiovio

public class NodeStack<E> implements Stack<E> {

    @Override
    public void push(E element)  {
        Node<E> temp = new Node<E>(element,stack);
        stack = temp;
        ++number_of_elements;
    }


    @Override
    public E top() throws EmptyStackException {
        if (isEmpty())
            throw new EmptyStackException();
            return stack.getElement();
    }

    @Override
    public E pop() throws EmptyStackException {
        Node<E> to_return;
        if (isEmpty()) {
            throw  new EmptyStackException();
        }else{
            to_return = stack;
            stack = stack.getNext();
            --number_of_elements;
            return to_return.getElement();
        }
    }

    @Override
    public boolean isEmpty() {
        if (size() < 1)
            return true;
            return false;
    }



    @Override
    public int size() {
        return number_of_elements;
    }

    @Override
    public String toString() {
        String to_return = "";
        to_return = to_return + "[";

        for (  Node<E> temp = stack; temp != null ; temp = temp.getNext()){

            if ( temp.getNext() == null){
                to_return+=(temp.getElement().toString());
            }else{
                to_return+=( temp.getElement().toString() + ",");
            }
        }
        to_return = to_return + "]";

        return to_return;
    }


    private Node<E> stack = null;
    private int number_of_elements = 0;

}