content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  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"));
      }
  }
  