@Override
 public int compare(AddressNode an1, AddressNode an2) {
   Address a1 = an1.getAddress();
   Address a2 = an2.getAddress();
   int result = ObjectUtils.compare(a1.getCityName(), a2.getCityName());
   if (result == 0) {
     result = ObjectUtils.compare(a1.getPostcode(), a2.getPostcode());
   }
   ;
   if (result == 0) {
     result = ObjectUtils.compare(a1.getStreetName(), a2.getStreetName());
   }
   ;
   if (result == 0) {
     result = ObjectUtils.compare(a1.getHouseNumber(), a2.getHouseNumber());
   }
   ;
   return result;
 }