Can someone re-write this Java 8 Stream?

IamtheWalrus

    public long getDiscountedPrice(Discount... discounts) {

        long discountSum = stream(discounts)
                .mapToLong(d -> d.discount(unmodifiableList(items)))
                .sum();
        return totalPrice - discountSum;
    }

public interface Discount {

    BigDecimal discount(List<String> items);
}

Currently, d.discount() returns a float. I want to change it to return BigDecimal because it's currency. Can someone help me rewritd this method? I'm new to Java 8.

IamtheWalrus

Or even in Java 6?

IamtheWalrus

Java 2?

Senna

I'm only learning java so my help is limited and you probably know a lot more that me, but....

Is this code working as a long (similar to float) at the moment? If it is then the discountSum variable is working as a long when it's taking in a BigDecimal, without the need to cast.

The return type of getDiscountPrice is a long.
In the method you have discountSum declared also as a long.
By changing both of those to BigDecimal would be a start, but as I'm unfamiliar with BigDecimal I'm not sure if it's that easy.

IamtheWalrus

private BigDecimal itemsDiscountFor(Discount[] discounts) {
        return stream(discounts)
                .map(d -> d.discount(unmodifiableList(items)))
                .reduce(ZERO, BigDecimal::add);
    }