adding MathContextin stream

Question

I have this piece of code that sets a BigDecimal:

setTotalDogsCurrentValueInUsd(
            purchases
                .stream()
                .map(p -> p.getNumberOfDogs())
                .filter(Objects::nonNull)
                .reduce(BigDecimal.ZERO, BigDecimal::add).multiply(new BigDecimal(rate)));

I would like to add MathContext.DECIMAL32 to round but I don't know where to add it exaclty

Answer 1

use this overload of multiply:

.multiply(new BigDecimal(rate), MathContext.DECIMAL32)

or if you want to apply it during the reduce call:

.reduce(BigDecimal.ZERO, (a, b) -> a.add(b,  MathContext.DECIMAL32))