Listing B

// Listing B

/**

 * @return Iterator filled with Strings representing user names

 */

public Iterator getUsers() {

    final ResultSet rs = userDbQuery();
 

    return new Iterator() {

        private Object next;
       

        public boolean hasNext() {

            if (next == null) {

               if (! rs.next()) {

                    return false;

                }

                next = rs.getString(1);

            }

            return true;

        }
       

        public Object next() {

            if (! hasNext()) {

               throw new NoSuchElementException();

            }

            String retval = next;

            next = null;

            return retval;

        }
       

        public void remove() {

            throw new UnsupportedOperationException("no remove allowed");

        }

    }

}