content: package backtype.storm.drpc;
  
  import backtype.storm.task.TopologyContext;
  import backtype.storm.topology.BasicOutputCollector;
  import backtype.storm.topology.OutputFieldsDeclarer;
  import backtype.storm.topology.base.BaseBasicBolt;
  import backtype.storm.tuple.Fields;
  import backtype.storm.tuple.Tuple;
  import backtype.storm.tuple.Values;
  import java.util.Map;
  import java.util.Random;
  import backtype.storm.utils.Utils;
  
  
  public class PrepareRequest extends BaseBasicBolt {
      public static final String ARGS_STREAM = Utils.DEFAULT_STREAM_ID;
      public static final String RETURN_STREAM = "ret";
      public static final String ID_STREAM = "id";
  
      Random rand;
  
      @Override
      public void prepare(Map map, TopologyContext context) {
          rand = new Random();
      }
  
      @Override
      public void execute(Tuple tuple, BasicOutputCollector collector) {
          String args = tuple.getString(0);
          String returnInfo = tuple.getString(1);
          long requestId = rand.nextLong();
          collector.emit(ARGS_STREAM, new Values(requestId, args));
          collector.emit(RETURN_STREAM, new Values(requestId, returnInfo));
          collector.emit(ID_STREAM, new Values(requestId));
      }
  
      public void declareOutputFields(OutputFieldsDeclarer declarer) {
          declarer.declareStream(ARGS_STREAM, new Fields("request", "args"));
          declarer.declareStream(RETURN_STREAM, new Fields("request", "return"));
          declarer.declareStream(ID_STREAM, new Fields("request"));
      }
  }
  