import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class FailFastManual {
    public static void main(String[] args) throws InterruptedException {
        ExecutorService eksekutor = Executors.newFixedThreadPool(3);
        List<Callable<Integer>> sumberData = List.of(
                () -> {                       // sumber-1: cepat dan sehat
                    Thread.sleep(30);
                    return 10;
                },
                () -> {                       // sumber-2: gagal seketika
                    throw new IllegalStateException("sumber-2 tidak merespons");
                },
                () -> {                       // sumber-3: lambat tapi sehat
                    Thread.sleep(2_000);
                    return 30;
                });

        // Pola fail-fast manual: kirim semuanya, berhenti di kegagalan
        // pertama, batalkan sisanya -- inti semantik "shutdown on failure".
        List<Future<Integer>> futures = new ArrayList<>();
        for (Callable<Integer> tugas : sumberData) {
            futures.add(eksekutor.submit(tugas));
        }

        List<Integer> hasil = new ArrayList<>();
        String kegagalan = null;
        try {
            for (Future<Integer> f : futures) {
                hasil.add(f.get()); // berhenti pada task pertama yang gagal
            }
        } catch (ExecutionException e) {
            for (Future<Integer> f : futures) {
                f.cancel(true); // interupsi task yang masih berjalan
            }
            kegagalan = e.getCause().getMessage();
        } finally {
            eksekutor.shutdown();
        }

        System.out.println("hasil terkumpul  : " + hasil);
        System.out.println("task yang gagal  : " + kegagalan);
        System.out.println("task-3 dibatalkan: " + futures.get(2).isCancelled());
    }
}