How to use

ReturnResults

in

org.apache.storm.drpc

public static void main(String[] args) throws Exception {
  TopologyBuilder builder = new TopologyBuilder();
  DRPCSpout spout = new DRPCSpout("exclamation");
  builder.setSpout("drpc", spout);
  builder.setBolt("exclaim", new ExclamationBolt(), 3).shuffleGrouping("drpc");
  builder.setBolt("return", new ReturnResults(), 3).shuffleGrouping("exclaim");
  Config conf = new Config();
  StormSubmitter.submitTopology("exclaim", conf, builder.createTopology());
  try (DRPCClient drpc = DRPCClient.getConfiguredClient(conf)) {
    System.out.println(drpc.execute("exclamation", "aaa"));
    System.out.println(drpc.execute("exclamation", "bbb"));
  }
}

  _collector.fail(input);
reconnectClient((DRPCInvocationsClient) client);

 /**
 * Creates and initializes a Publisher that writes to the DRPC servers. Intended to be used inside a Storm
 * bolt in a Storm topology.
 *
 * @param config Needs the Storm configuration {@link Map} in {@link com.yahoo.bullet.storm.BulletStormConfig#STORM_CONFIG}.
 */
public DRPCResultPublisher(BulletConfig config) {
  // Get the Storm Config that has all the relevant cluster settings and properties
  Map stormConfig = config.getRequiredConfigAs(DRPCConfig.STORM_CONFIG, Map.class);
  collector = new DRPCOutputCollector();
  // Wrap the collector in a OutputCollector (it just delegates to the underlying DRPCOutputCollector)
  OutputCollector boltOutputCollector = new OutputCollector(collector);
  bolt = new ReturnResults();
  // No need for a TopologyContext
  bolt.prepare(stormConfig, null, boltOutputCollector);
}

  @Override
  public void close() {
    bolt.cleanup();
  }
}

@Override
public void send(PubSubMessage message) throws PubSubException {
  Metadata metadata = message.getMetadata();
  // Remove the content
  String content = metadata.getContent().toString();
  log.debug("Removing metadata {} for result {}@{}: {}", content, message.getId(), message.getSequence(), message.getContent());
  metadata.setContent(null);
  String serializedMessage = message.asJSON();
  Tuple tuple = new DRPCTuple(new Values(serializedMessage, content));
  // This sends the message through DRPC and not to the collector but it acks or fails accordingly.
  bolt.execute(tuple);
  if (!collector.isAcked()) {
    throw new PubSubException("Message not acked. Unable to send message through DRPC:\n " + serializedMessage);
  }
  // Otherwise, we're good to proceed
  collector.reset();
}

 /**
 * Creates and initializes a Publisher that writes to the DRPC servers. Intended to be used inside a Storm
 * bolt in a Storm topology.
 *
 * @param config Needs the Storm configuration {@link Map} in {@link com.yahoo.bullet.storm.BulletStormConfig#STORM_CONFIG}.
 */
public DRPCResultPublisher(BulletConfig config) {
  // Get the Storm Config that has all the relevant cluster settings and properties
  Map stormConfig = config.getRequiredConfigAs(DRPCConfig.STORM_CONFIG, Map.class);
  collector = new DRPCOutputCollector();
  // Wrap the collector in a OutputCollector (it just delegates to the underlying DRPCOutputCollector)
  OutputCollector boltOutputCollector = new OutputCollector(collector);
  bolt = new ReturnResults();
  // No need for a TopologyContext
  bolt.prepare(stormConfig, null, boltOutputCollector);
}

  @Override
  public void close() {
    bolt.cleanup();
  }
}

@Override
public void send(PubSubMessage message) throws PubSubException {
  Metadata metadata = message.getMetadata();
  // Remove the content
  String content = metadata.getContent().toString();
  log.debug("Removing metadata {} for result {}@{}: {}", content, message.getId(), message.getSequence(), message.getContent());
  metadata.setContent(null);
  String serializedMessage = message.asJSON();
  Tuple tuple = new DRPCTuple(new Values(serializedMessage, content));
  // This sends the message through DRPC and not to the collector but it acks or fails accordingly.
  bolt.execute(tuple);
  if (!collector.isAcked()) {
    throw new PubSubException("Message not acked. Unable to send message through DRPC:\n " + serializedMessage);
  }
  // Otherwise, we're good to proceed
  collector.reset();
}

    .fieldsGrouping(PREPARE_ID, PrepareRequest.RETURN_STREAM, new Fields("request"));
i++;
builder.setBolt(boltId(i), new ReturnResults())
    .noneGrouping(boltId(i - 1));
return builder.createTopology();

  _collector.fail(input);
reconnectClient((DRPCInvocationsClient) client);

    .fieldsGrouping(PREPARE_ID, PrepareRequest.RETURN_STREAM, new Fields("request"));
i++;
builder.setBolt(boltId(i), new ReturnResults())
    .noneGrouping(boltId(i-1));
return builder.createTopology();