Java で Future のリストを効率的に管理し、例外を処理するにはどうすればよいですか?

<code class="java">Executor executor = Executors.newFixedThreadPool(4);
CompletionService<SomeResult> completionService = new ExecutorCompletionService<>(executor);

// 4 tasks
for (int i = 0; i < 4; i++) {
    completionService.submit(new Callable<SomeResult>() {
        public SomeResult call() {
            // ... task implementation
            return result;
        }
    });
}

int received = 0;
boolean errors = false;

while (received < 4 && !errors) {
    Future<SomeResult> resultFuture = completionService.take(); // Blocks if none available
    try {
        SomeResult result = resultFuture.get();
        received++;
        // ... do something with the result
    } catch (Exception e) {
        // Log the exception
        errors = true;
    }
}

// Potentially consider canceling any still running tasks if errors occurred</code>