java.util.NoSuchElementException: No value present

Asked Jan 28 '19 at 11:28

Active Jan 28 '19 at 11:35

Viewed 914 times

I'm getting this exception when trying to peek an object from an ArrayList based on the min value of an attribute.

Here is a snapchatCode from my program:

return individuals.stream()
                .parallel()
                .filter(s -> s.getFitness() != fittest.getFitness())
                .min(Comparator.comparingInt(object -> object.getFitness()))
                .get();

individuals is an ArrayList<Individual>.

class Individual{
        int fitness;
        public int getFitness() {
            return fitness;
        }
    }

The exception i'm getting on the get() method:

Exception in thread "main" java.util.NoSuchElementException: No value
 present

After debugging my program i found that all the individuals of the stream have the same fitness value, so after the filter operation no individual is found, so hen we call the get() we have an exception.

How can I manage to get a random value in the case where all the individual have the same fitness value.

edited Jan 28 '19 at 11:35

Vikrant Kashyap

6,398
3
32
52

asked Jan 28 '19 at 11:28

xmen-5

1,806
1
23
44

1

There is something called `optional`. – Vishwa Ratna Jan 28 '19 at 11:31
A random value, would that mean a newly constructed `Individual` object with random content? Or? – Ole V.V. Jan 28 '19 at 11:32
2

`.filter(s -> s.getFitness() <= fittest.getFitness())` ? ...or even`!s.equals(fittest)`... – xerx593 Jan 28 '19 at 11:33
Random number for what? Let's say you have `Individual@1{fintess=1}` and `Individual@2{fintess=1}`, which one should receive a new random number? – J-Alex Jan 28 '19 at 11:33
Use `Optional.orElse(defaultValue)` – NiVeR Jan 28 '19 at 11:34
@OleV.V. I mean a random individual from the list of individduals, as all the individuals has the same fitness value. – xmen-5 Jan 28 '19 at 11:43
1

@xerx593 your first proposition worked fine. – xmen-5 Jan 28 '19 at 11:47

java.util.NoSuchElementException: No value present

0 Answers0