先物を扱う際にエラーや早期終了を効率的に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<SomeResult>(executor);

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

int received = 0;
boolean errors = false;

while(received < 4 && !errors) {
      Future<SomeResult> resultFuture = completionService.take(); // Blocks until available
      try {
         SomeResult result = resultFuture.get();
         received ++;
         // Process the result
      }
      catch(Exception e) {
         // Log or handle the error
         errors = true;
      }

      if (errors) {
         // Cancel any remaining tasks
         executor.shutdown();
         break;
      }
}</code>