code: public static List<GatewayAddress> asList(final String addresses) {
          if (addresses == null) {
              throw new IllegalArgumentException("addresses must not be null");
          }
  
          List<GatewayAddress> list = new ArrayList<GatewayAddress>();
          final String[] tokens = addresses.split(",");
          if (tokens == null) {
              return list;
          }
  
          int id = 1;
          for (String token : tokens) {
              list.add(new GatewayAddress(id++, token));
          }
  
          return list;
      }
docs: As list.
  
  @param addresses the addresses
  @return the list