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.testing;
  
  import backtype.storm.coordination.BatchOutputCollector;
  import backtype.storm.task.TopologyContext;
  import backtype.storm.topology.OutputFieldsDeclarer;
  import backtype.storm.topology.base.BaseBatchBolt;
  import backtype.storm.tuple.Fields;
  import backtype.storm.tuple.Tuple;
  import backtype.storm.tuple.Values;
  import backtype.storm.utils.Utils;
  import clojure.lang.Numbers;
  import java.util.HashMap;
  import java.util.Map;
  
  public class KeyedSummingBatchBolt extends BaseBatchBolt {
      BatchOutputCollector _collector;
      Object _id;
      Map<Object, Number> _sums = new HashMap<Object, Number>();
  
      @Override
      public void prepare(Map conf, TopologyContext context, BatchOutputCollector collector, Object id) {
          _collector = collector;
          _id = id;
      }
  
      @Override
      public void execute(Tuple tuple) {
          Object key = tuple.getValue(1);
          Number curr = Utils.get(_sums, key, 0);
          _sums.put(key, Numbers.add(curr, tuple.getValue(2)));
      }
  
      @Override
      public void finishBatch() {
          for (Object key : _sums.keySet()) {
              _collector.emit(new Values(_id, key, _sums.get(key)));
          }
      }
  
      @Override
      public void declareOutputFields(OutputFieldsDeclarer declarer) {
          declarer.declare(new Fields("tx", "key", "sum"));
      }
  }
  