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.planner.processor;
  
  import backtype.storm.task.TopologyContext;
  import backtype.storm.tuple.Fields;
  import java.util.List;
  import java.util.Map;
  import storm.trident.operation.Aggregator;
  import storm.trident.operation.TridentOperationContext;
  import storm.trident.planner.ProcessorContext;
  import storm.trident.planner.TridentProcessor;
  import storm.trident.tuple.TridentTuple;
  import storm.trident.tuple.TridentTuple.Factory;
  import storm.trident.tuple.TridentTupleView.ProjectionFactory;
  
  public class AggregateProcessor implements TridentProcessor {
      Aggregator _agg;
      TridentContext _context;
      FreshCollector _collector;
      Fields _inputFields;
      ProjectionFactory _projection;
  
      public AggregateProcessor(Fields inputFields, Aggregator agg) {
          _agg = agg;
          _inputFields = inputFields;
      }
  
      @Override
      public void prepare(Map conf, TopologyContext context, TridentContext tridentContext) {
          List<Factory> parents = tridentContext.getParentTupleFactories();
          if (parents.size() != 1) {
              throw new RuntimeException("Aggregate operation can only have one parent");
          }
          _context = tridentContext;
          _collector = new FreshCollector(tridentContext);
          _projection = new ProjectionFactory(parents.get(0), _inputFields);
          _agg.prepare(conf, new TridentOperationContext(context, _projection));
      }
  
      @Override
      public void cleanup() {
          _agg.cleanup();
      }
  
      @Override
      public void startBatch(ProcessorContext processorContext) {
          _collector.setContext(processorContext);
          processorContext.state[_context.getStateIndex()] = _agg.init(processorContext.batchId, _collector);
      }
  
      @Override
      public void execute(ProcessorContext processorContext, String streamId, TridentTuple tuple) {
          _collector.setContext(processorContext);
          _agg.aggregate(processorContext.state[_context.getStateIndex()], _projection.create(tuple), _collector);
      }
  
      @Override
      public void finishBatch(ProcessorContext processorContext) {
          _collector.setContext(processorContext);
          _agg.complete(processorContext.state[_context.getStateIndex()], _collector);
      }
  
      @Override
      public Factory getOutputFactory() {
          return _collector.getOutputFactory();
      }
  }
  