public void addItem(Item item, int count) throws ItemOutOfStockException  {

        if (count > 10) throw new ItemOutOfStockException(item);

        for (int i = 0; i < items.size(); i++) //
            if (items.contains(item))
                items.remove(items.indexOf(item));

        for (int i = 0; i < count; i++)
            items.add(item);
    }