code: @VisibleForTesting
      protected int intToInt(final Integer exp) {
          final Integer value = fieldConstraints.getIntMappingValue(exp);
          if (value != null) {
              return value;
          }
          return exp;
      }
docs: Maps integer values to another integer equivalence. Always consider mapping higher integers to lower once. Ex.: if 0 and 7 mean the
  same, map 7 to 0.
  
  @param exp - integer to be mapped
  @return Mapping integer. If no mapping int is found, will return exp