AddItem(S)
{
    if (firstItem == null)
        firstItem = lastItem = new Item(S);
    else
    {
        Item sortingItem = firstItem;
        Item newItem = new Item(S);

        // Logic for when only 1 item is in the array
        // because while will not run in this case

        while(sortingItem.hasNext())
        {
            if (sortingItem.compareTo(newItem) < 0)
            {
                newItem.setPrevious(sortingItem.previous);
                sortingItem.setPrevious(newItem);
                newItem.setNext(sortinItem);
                if(newItem.previous = null)
                    firstItem = newItem;
                else
                    newItem.previous.setNext(newItem);
            }
        }
    }
}