content: package backtype.storm.drpc;
  
  import backtype.storm.Config;
  import backtype.storm.generated.DistributedRPCInvocations;
  import backtype.storm.task.OutputCollector;
  import backtype.storm.task.TopologyContext;
  import backtype.storm.topology.OutputFieldsDeclarer;
  import backtype.storm.topology.base.BaseRichBolt;
  import backtype.storm.tuple.Tuple;
  import backtype.storm.utils.ServiceRegistry;
  import backtype.storm.utils.Utils;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import org.apache.log4j.Logger;
  import org.apache.thrift7.TException;
  import org.json.simple.JSONValue;
  
  
  public class ReturnResults extends BaseRichBolt {
      public static final Logger LOG = Logger.getLogger(ReturnResults.class);
      OutputCollector _collector;
      boolean local;
  
      Map<List, DRPCInvocationsClient> _clients = new HashMap<List, DRPCInvocationsClient>();
  
      @Override
      public void prepare(Map stormConf, TopologyContext context, OutputCollector collector) {
          _collector = collector;
          local = stormConf.get(Config.STORM_CLUSTER_MODE).equals("local");
      }
  
      @Override
      public void execute(Tuple input) {
          String result = (String) input.getValue(0);
          String returnInfo = (String) input.getValue(1);
          if(returnInfo!=null) {
              Map retMap = (Map) JSONValue.parse(returnInfo);
              final String host = (String) retMap.get("host");
              final int port = Utils.getInt(retMap.get("port"));
              String id = (String) retMap.get("id");
              DistributedRPCInvocations.Iface client;
              if(local) {
                  client = (DistributedRPCInvocations.Iface) ServiceRegistry.getService(host);
              } else {
                  List server = new ArrayList() {{
                      add(host);
                      add(port);
                  }};
              
                  if(!_clients.containsKey(server)) {
                      _clients.put(server, new DRPCInvocationsClient(host, port));
                  }
                  client = _clients.get(server);
              }
                  
              try {
                  client.result(id, result);
                  _collector.ack(input);
              } catch(TException e) {
                  LOG.error("Failed to return results to DRPC server", e);
                  _collector.fail(input);
              }
          }
      }    
  
      @Override
      public void cleanup() {
          for(DRPCInvocationsClient c: _clients.values()) {
              c.close();
          }
      }
  
      public void declareOutputFields(OutputFieldsDeclarer declarer) {
      }
  }
  