static AttributeInfo lookup(LinkedList list, String name) {
        if (list == null)
            return null;

        ListIterator iterator = list.listIterator();
        while (iterator.hasNext()) {
            AttributeInfo ai = (AttributeInfo)iterator.next();
            if (ai.getName().equals(name))
                return ai;
        }

        return null;            // no such attribute
    }