How to use

org.apache.storm.drpc.ReturnResults

constructor

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"));
  }
}

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

 /**
 * 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);
}

 /**
 * 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);
}

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