code: private void setMapTupleValues(Tuple tuple, int position, Object value, AbstractType<?> validator) throws ExecException
      {
          AbstractType<?> keyValidator = ((MapType<?, ?>) validator).getKeysType();
          AbstractType<?> valueValidator = ((MapType<?, ?>) validator).getValuesType();
  
          int i = 0;
          Tuple innerTuple = TupleFactory.getInstance().newTuple(((Map<?,?>) value).size());
          for(Map.Entry<?,?> entry :  ((Map<Object, Object>)value).entrySet())
          {
              Tuple mapEntryTuple = TupleFactory.getInstance().newTuple(2);
              setTupleValue(mapEntryTuple, 0, cassandraToPigData(entry.getKey(), keyValidator), keyValidator);
              setTupleValue(mapEntryTuple, 1, cassandraToPigData(entry.getValue(), valueValidator), valueValidator);
              innerTuple.set(i, mapEntryTuple);
              i++;
          }
          tuple.set(position, innerTuple);
      }
docs: set the values of set/list at and after the position of the tuple