class AddrBook
    {
        /* var to hold the collection of Addr
         * 
         * @visible private
         * @type ArrayList
         */
        protected ArrayList book
        {
            get { return book; }
        }

        /* constructor
         * 
         * @param Addr addr
         * @visible public
         * @returns void
         */
        public AddrBook(Addr addr)
        {
            book = new ArrayList();
            book.Add = addr;
        }