javademos/structured-concurrency-final/src/RandomTasks.java

import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.StructuredTaskScope.Joiner;

/** Five tasks that sleep a random time and fail if they were "too slow". Seeded, so the transcript is repeatable. */
public class RandomTasks {

    static class TooSlowException extends Exception {
        TooSlowException(String m) { super(m); }
    }

    public static void main(String[] args) throws Exception {
        long seed = Long.parseLong(args[0]);
        int threshold = 700;
        Random random = new Random(seed);
        List<Callable<Integer>> tasks = new ArrayList<>();
        for (int i = 0; i < 5; i++) {
            int duration = random.nextInt(1000);
            System.out.println("Duration: " + duration);
            tasks.add(() -> {
                Thread.sleep(duration);
                if (duration > threshold) throw new TooSlowException("Duration " + duration + " greater than threshold " + threshold);
                return duration;
            });
        }
        try (var scope = StructuredTaskScope.open(Joiner.<Integer>allSuccessfulOrThrow())) {
            tasks.forEach(scope::fork);
            for (int r : scope.join()) System.out.println("Result: " + r);
        } catch (ExecutionException e) {
            System.out.println("ExecutionException: " + e.getCause().getClass().getSimpleName() + ": " + e.getCause().getMessage());
        }
    }
}