1. processMessage method returns a completion stage.

CompletionStage<PubsubMessage> processedMessage = processMessage(message, parsedMessage)

while getPublishers returns a List of publishers.

protected List<MessagePublisher> getPublishers() {
    return stepConfig.getPublishers().values().stream().toList();
  }

2. All the publishers have to publish the processedMessage

CompletionStage<Stream<CompletionStage<String>>> streamCompletionStage = processedMessage.thenApply(
   pubsubMessage -> {
     return getPublishers().stream()
          .map(messagePublisher -> messagePublisher.publish(pubsubMessage));
    });

3. Previously getPublisher was just returning a single publisher, and I was able to do the following:

    return processMessage(message, parsedMessage)
        .thenApply(pubsubMessage -> getPublisher().publish(pubsubMessage))
        .thenApply(
            result -> {
              try {
                return Result.ACK;
              } catch (Exception e) {
                return Result.NACK;
              }
            });

4. I have to return Return.NACK even if one of the try's fail, Result.ACK otherwise.

My knowledge of java concurrent is somewhat limited and I am not sure how to go about it, any suggestions/help will be welcome.