非同期コール・モデル

static class SomeClass {
  public static void main(String[] args) {
    Engine engine = new Engine("worker-pool");

    Fiber fiber = engine.createFiber();

    Step step = new StepOne(new StepTwo(new StepThree(null)));
      Packet packet = new Packet();

    fiber.start(
        step,
        packet,
        new CompletionCallback() {
          @Override
          public void onCompletion(Packet packet) {
            // Fiber has completed successfully
          }

          @Override
          public void onThrowable(Packet packet, Throwable throwable) {
            // Fiber processing was terminated with an exception
          }
        });
  }
}

    static class StepTwo extends Step {
      public StepTwo(Step next) {
        super(next);
      }

      @Override
      public NextAction apply(Packet packet) {
        return doSuspend((fiber) -> {
          // The Fiber is now suspended
          // Start the asynchronous call
          try {
            Path path = Paths.get(URI.create(this.getClass().getResource("/somefile.dat").toString()));
            AsynchronousFileChannel fileChannel =
                AsynchronousFileChannel.open(path, StandardOpenOption.READ);

            ByteBuffer buffer = ByteBuffer.allocate(1024);
            fileChannel.read(buffer, 0, buffer, new CompletionHandler<Integer, ByteBuffer>() {
              @Override
              void completed(Integer result, ByteBuffer attachment) {
                // Store data in Packet and resume Fiber
                packet.put("DATA_SIZE_READ", result);
                packet.put("DATA_FROM_SOMEFILE", attachment);
                fiber.resume(packet);
              }

              @Override
              public void failed(Throwable exc, ByteBuffer attachment) {
                // log exc
                completed(0, null);
              }
            });
          } catch (IOException e) {
            // log exception
            // If not resumed here, Fiber will never be resumed
          }
        });
      }
    }

    static class StepOne extends Step {
      public StepOne(Step next) {
        super(next);
      }

      @Override
      public NextAction apply(Packet packet) {
        String namespace = "default";
        Step step = CallBuilder.create().with($ -> {
          $.labelSelector = "weblogic.clusterName=cluster-1";
          $.limit = 50;
          $.timeoutSeconds = 30;
        }).listPodAsync(namespace, new ResponseStep<V1PodList>(next) {
          @Override
          public NextAction onFailure(Packet packet, ApiException e, int statusCode,
              Map<String, List<String>> responseHeaders) {
            if (statusCode == CallBuilder.NOT_FOUND) {
              return onSuccess(packet, null, statusCode, responseHeaders);
            }
            return super.onFailure(packet, e, statusCode, responseHeaders);
          }

          @Override
          NextAction onSuccess(Packet packet, V1PodList result, int statusCode,
              Map<String, List<String>> responseHeaders) {
            // do something with the result Pod, if not null
            return doNext(packet);
          }
        });

        return doNext(step, packet);
      }
    }