import java.util.concurrent.CompletableFuture;
import java.util.List;
import java.util.stream.Collectors;

public class AllOfResults {
    
    public static void main(String[] args) {
        List<CompletableFuture<String>> futures = List.of(
            CompletableFuture.supplyAsync(() -> "Result 1"),
            CompletableFuture.supplyAsync(() -> "Result 2"),
            CompletableFuture.supplyAsync(() -> "Result 3")
        );
        
        //allOf возвращает Void — результаты не доступны
        CompletableFuture<Void> all = CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]));
        all.join(); // ждем завершения, но результатов нет
        
        //Собираем результаты вручную через thenApply
        CompletableFuture<List<String>> combined = CompletableFuture
            .allOf(futures.toArray(new CompletableFuture[0]))
            .thenApply(v -> futures.stream()
                .map(CompletableFuture::join)
                .collect(Collectors.toList()));
        
        List<String> results = combined.join();
        System.out.println(results); // [Result 1, Result 2, Result 3]
        
        // ✅ Альтернатива: использование thenAccept для побочного эффекта
        CompletableFuture<Void> log = CompletableFuture
            .allOf(futures.toArray(new CompletableFuture[0]))
            .thenAccept(v -> futures.forEach(f -> System.out.println(f.join())));
        log.join();
        
        //Сборка с преобразованием типов
        CompletableFuture<Integer> totalLength = CompletableFuture
            .allOf(futures.toArray(new CompletableFuture[0]))
            .thenApply(v -> futures.stream()
                .map(CompletableFuture::join)
                .mapToInt(String::length)
                .sum());
        System.out.println("Total length: " + totalLength.join());
    }
}

import java.util.concurrent.CompletableFuture;

public class Task020726 {
    public static void main(String[] args) throws Exception {
        CompletableFuture<Integer> f1 = CompletableFuture.completedFuture(42);
        CompletableFuture<String> f2 = CompletableFuture.completedFuture("hello");
        CompletableFuture<Void> all = CompletableFuture.allOf(f1, f2);
        System.out.println(all.get());
    }
}