How to use

addMessages

method

in

com.google.pubsub.v1.PublishRequest$Builder

@Override
public int publish(TopicPath topic, List<OutgoingMessage> outgoingMessages) throws IOException {
 PublishRequest.Builder request = PublishRequest.newBuilder().setTopic(topic.getPath());
 for (OutgoingMessage outgoingMessage : outgoingMessages) {
  PubsubMessage.Builder message =
    PubsubMessage.newBuilder().setData(ByteString.copyFrom(outgoingMessage.elementBytes));
  if (outgoingMessage.attributes != null) {
   message.putAllAttributes(outgoingMessage.attributes);
  }
  if (timestampAttribute != null) {
   message
     .getMutableAttributes()
     .put(timestampAttribute, String.valueOf(outgoingMessage.timestampMsSinceEpoch));
  }
  if (idAttribute != null && !Strings.isNullOrEmpty(outgoingMessage.recordId)) {
   message.getMutableAttributes().put(idAttribute, outgoingMessage.recordId);
  }
  request.addMessages(message);
 }
 PublishResponse response = publisherStub().publish(request.build());
 return response.getMessageIdsCount();
}

publishRequest.setTopic(topicName);
for (OutstandingPublish outstandingPublish : outstandingBatch.outstandingPublishes) {
 publishRequest.addMessages(outstandingPublish.message);