code: public RoundingQueryBuilder setCurrency(CurrencyUnit currencyUnit) {
          Objects.requireNonNull(currencyUnit);
          set(CurrencyUnit.class, currencyUnit);
          return this;
      }
docs: Sets the target {@link CurrencyUnit}, which defines a rounding targeting a concrete {@link
  CurrencyUnit}.
  Typically this determines all other properties, such as scale and the concrete rounding algorithm. With
  rounding names, depending on the implementation, additional subselections are possible. Similarly
  additional attributes can be used to select special rounding instances, e.g. for cash rounding.
  
  @param currencyUnit the target {@link CurrencyUnit} not null.
  @return this instance for chaining