@Getter
public class Dish {
BigDecimal price;
}
I need to calculate the total price of all ordered dishes, but I fail to write the reduce method. This is a method signature ( argument has a map of Dish and how many times it was ordered ).
So it must be something like this sum of every dish.getPrice * dishQuantaty
private BigDecimal getOrderTotalPrice(Map<Dish, Integer> dishQuantityMap) {
}
The fail-code I was asked about
return dishQuantityMap.entrySet().stream()
.reduce(BigDecimal.ZERO,
(dishIntegerEntry) ->
dishIntegerEntry.getKey().getPrice()
.multiply(BigDecimal.valueOf(dishIntegerEntry.getValue())));
Did you mean something like this:
private BigDecimal getOrderTotalPrice(Map<Dish, Integer> dishQuantityMap) {
return dishQuantityMap.entrySet().stream()
.map(d -> d.getKey().getPrice().multiply(new BigDecimal(d.getValue())))
.reduce(BigDecimal.ZERO, BigDecimal::add);
}