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 storm.trident.state.map;
  
  import backtype.storm.tuple.Fields;
  import backtype.storm.tuple.Values;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import storm.trident.operation.CombinerAggregator;
  import storm.trident.operation.TridentCollector;
  import storm.trident.operation.TridentOperationContext;
  import storm.trident.state.CombinerValueUpdater;
  import storm.trident.state.StateUpdater;
  import storm.trident.state.ValueUpdater;
  import storm.trident.tuple.ComboList;
  import storm.trident.tuple.TridentTuple;
  import storm.trident.tuple.TridentTupleView.ProjectionFactory;
  
  public class MapCombinerAggStateUpdater implements StateUpdater<MapState> {
      private static final long serialVersionUID = -3960578785572592092L;
      CombinerAggregator _agg;
      Fields _groupFields;
      Fields _inputFields;
      transient ProjectionFactory _groupFactory;
      transient ProjectionFactory _inputFactory;
      ComboList.Factory _factory;
  
      public MapCombinerAggStateUpdater(CombinerAggregator agg, Fields groupFields, Fields inputFields) {
          _agg = agg;
          _groupFields = groupFields;
          _inputFields = inputFields;
          if (inputFields.size() != 1) {
              throw new IllegalArgumentException("Combiner aggs only take a single field as input. Got this instead: " + inputFields.toString());
          }
          _factory = new ComboList.Factory(groupFields.size(), inputFields.size());
      }
  
      @Override
      public void updateState(MapState map, List<TridentTuple> tuples, TridentCollector collector) {
          List<List<Object>> groups = new ArrayList<List<Object>>(tuples.size());
          List<ValueUpdater> updaters = new ArrayList<ValueUpdater>(tuples.size());
  
          for (TridentTuple t : tuples) {
              groups.add(_groupFactory.create(t));
              updaters.add(new CombinerValueUpdater(_agg, _inputFactory.create(t).getValue(0)));
          }
          List<Object> newVals = map.multiUpdate(groups, updaters);
  
          for (int i = 0; i < tuples.size(); i++) {
              List<Object> key = groups.get(i);
              Object result = newVals.get(i);
              collector.emit(_factory.create(new List[] { key, new Values(result) }));
          }
      }
  
      @Override
      public void prepare(Map conf, TridentOperationContext context) {
          _groupFactory = context.makeProjectionFactory(_groupFields);
          _inputFactory = context.makeProjectionFactory(_inputFields);
      }
  
      @Override
      public void cleanup() {
      }
  
  }
  