Stormクラスタ上のTridentWordCountの計算結果を取得する方法

Stormクラスタ上のトポロジは継続的に計算されるため、HadoopがHDFS上に計算結果を保存するようなものではない.クラスタ上にコミットされたトポロジでは、データベースやローカルファイルなどの計算結果の出力位置をユーザーがプログラムを書くときに指定する必要があるため、TridentWordCountを実行するときにDRPCStreamを設定してTridentの状態をクエリーし、いくつかの単語の統計結果をクエリーすることができる.storm-starterの例ではローカルモードでlocalDRPCを使用してクエリーして出力するコードのみが与えられているため、クラスタにコミットした後も計算が継続して結果出力がないため、クラスタにコミットした後にDRPCClientを起動して計算結果を取得するようにプログラムを変更し、プログラムは以下のように変更されます.

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 * to you under the Apache License, Version 2.0 (the
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 * http://www.apache.org/licenses/LICENSE-2.0
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package storm.starter.trident;

import backtype.storm.Config;
import backtype.storm.LocalCluster;
import backtype.storm.LocalDRPC;
import backtype.storm.StormSubmitter;
import backtype.storm.generated.StormTopology;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;
import backtype.storm.utils.DRPCClient;//DRPC    
import storm.trident.TridentState;
import storm.trident.TridentTopology;
import storm.trident.operation.BaseFunction;
import storm.trident.operation.TridentCollector;
import storm.trident.operation.builtin.Count;
import storm.trident.operation.builtin.FilterNull;
import storm.trident.operation.builtin.MapGet;
import storm.trident.operation.builtin.Sum;
import storm.trident.testing.FixedBatchSpout;
import storm.trident.testing.MemoryMapState;
import storm.trident.tuple.TridentTuple;


public class TridentWordCount {
  public static class Split extends BaseFunction {
    @Override
    public void execute(TridentTuple tuple, TridentCollector collector) {
      String sentence = tuple.getString(0);
      for (String word : sentence.split(" ")) {
        collector.emit(new Values(word));
      }
    }
  }

  public static StormTopology buildTopology(DRPCClient drpc) {//     LocalDRPC   DRPCClient
    FixedBatchSpout spout = new FixedBatchSpout(new Fields("sentence"), 3, new Values("the cow jumped over the moon"),
        new Values("the man went to the store and bought some candy"), new Values("four score and seven years ago"),
        new Values("how many apples can you eat"), new Values("to be or not to be the person"));
    spout.setCycle(true);

    TridentTopology topology = new TridentTopology();
    TridentState wordCounts = topology.newStream("spout1", spout).parallelismHint(16).each(new Fields("sentence"),
        new Split(), new Fields("word")).groupBy(new Fields("word")).persistentAggregate(new MemoryMapState.Factory(),
        new Count(), new Fields("count")).parallelismHint(16);

    topology.newDRPCStream("words").each(new Fields("args"), new Split(), new Fields("word")).groupBy(new Fields(
        "word")).stateQuery(wordCounts, new Fields("word"), new MapGet(), new Fields("count")).each(new Fields("count"),
        new FilterNull()).aggregate(new Fields("count"), new Sum(), new Fields("sum"));
    return topology.build();
  }

  public static void main(String[] args) throws Exception {
    Config conf = new Config();
    conf.setMaxSpoutPending(20);
//    conf.setDebug(true);//  Spout Bolt   
/*    if (args.length == 0) {
      LocalDRPC drpc = new LocalDRPC();
      LocalCluster cluster = new LocalCluster();
      cluster.submitTopology("wordCounter", conf, buildTopology(drpc));
      for (int i = 0; i < 100; i++) {
        System.out.println("DRPC RESULT: " + drpc.execute("words", "jumped"));
        Thread.sleep(1000);
      }
    }
    else {*/
      conf.setNumWorkers(3);//    DRPC DRPC          ，          ，        
      DRPCClient client=new DRPCClient("drpc.server.location",3772);
      StormSubmitter.submitTopologyWithProgressBar(args[0], conf, buildTopology(client));
      
      while(true) {//     jumped the     
    	    System.out.println(client.execute("words", "jumped the"));
          Thread.sleep(1000);
        }
   // }
  }
}