CompletableFutureChallenge.java

import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.function.Supplier;
import java.util.stream.Collectors;
public class CompletableFutureChallenge{
    static ExecutorService executor = Executors.newCachedThreadPool();
    public static void main (String... oracleCodeOneAdventure) {
        CompletableFuture<List<String>> adventureStart = new CompletableFuture<>();
        Supplier<List<String>> sanFranSightSupplier = () -> List.of("Alcatraz", "Cable Car", "Golden Gate", "Lombard Street");

        adventureStart.completeAsync(sanFranSightSupplier, executor)
            .thenCompose(sights -> {
                return CompletableFuture.supplyAsync(() -> sights.stream()
                        .map(String::length)
                        .collect(Collectors.toList()));
            })
        .thenAccept(ratings -> {
            var rating = ratings.stream()
                .dropWhile(sightRating -> sightRating <= 12)
                .findFirst()
                .orElse(0);
            System.out.print("Rating: " + rating + " ");
        });

        System.out.print("Time to go home : ( ");
    }
}