package stack;

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

/**
 * Created with MONSTER.
 * User: xgiovio
 * Date: 05/03/14
 * Time: 0.12
 */


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

    @Override
    public void push(E element) throws FullStackException {
        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
    // not used
    public boolean isFull() {
            return false;
    }

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


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

}