How to convert a method returning List<String> into Reactive Stream smallrye mutiny?

Question

I am quite new to Reactive programming and would like to convert a method that returns List<Stirng> into a reactive stream approach using Smallrye Mutiny.

I tried creating Publisher etc but could not find the right example to proceed further. Can someone please provide some guidance or suggestion on this?

As provided below code, I have a method that will provide a list of random strings. Here I need to wait until all elements are being added to List before returning. I want to achieve the reactive stream approach where instead of waiting for all the elements to be added to the list I wish to return it as soon as generated.

I believe it's possible to achieve this using the SmallRye Mutiny, can you please let me know how to achieve the same?

import org.apache.commons.lang.RandomStringUtils;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.IntStream;

public class Main {
    public static void main(String[] args) {
        System.out.println(addElements(5));
    }

    private static List<String> addElements(final int elementsCount) {
        final List<String> returnList = new ArrayList<>();
        IntStream.range(0, elementsCount).forEach(count -> {
            returnList.add(RandomStringUtils.randomAlphanumeric(17).toUpperCase());
        });
        return returnList;
    }
}

Answer 1

Here's one way:

public class Main {

    public static void main(String[] args) {
        List<String> list = addElements(5).await().indefinetely();
        System.out.println(list);
    }

    private static Uni<List<String>> addElements(final int elementsCount) {
        return Multi.createFrom()
                .range( 0, elementCount )
                .map( integer -> RandomStringUtils.randomAlphanumeric( 17 ).toUpperCase() )
                .collect()
                .asList();
    }
}

For reference, on the official site there is a helpful Getting Started