CODEWITHSUNDEEP
java-8java-stream
hotmeatballsoup
hotmeatballsoup

Reputation: 625

Using Java Streams to process a list with multiple fields that impact the result

Java 8 here. I have the following POJO:

@Getter
@Setter
public class Orderline {
    private Integer qty;
    private BigDecimal price;
    private String productName; 
}

I'm looking for a Stream-y way of iterating through a List<Orderlines> and coming up with a subtotal based on their individual quantities and prices. The "old" (pre-Stream) way of doing this would look like:

List<Orderline> orderlines = order.getOrderlines();
double sub = 0.0;
for (Orderline ol : orderlines) {
    sub += ol.getQty() * ol.getPrice();
}

BigDecimal subtotal = BigDecimal.valueOf(sub);

My best attempt at using Streams to accomplish this is:

BigDecimal subtotal = order.getOrderlines().stream()
    .map(Orderline::getPrice)
    .reduce(BigDecimal.ZERO, BigDecimal::add);

However this doesn't take their quantities into consideration. Any ideas how I can accomplish this?

Upvotes: 1

Views: 196

Answers (1)

g_bor
g_bor

Reputation: 1092

You could use

map(x->x.getPrice().multiply(BigDecimal.valueOf(x.getQty())))

in your second line.

Upvotes: 2

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