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.operation.impl;
  
  import backtype.storm.tuple.Fields;
  import java.util.List;
  import java.util.Map;
  import storm.trident.operation.Aggregator;
  import storm.trident.operation.TridentCollector;
  import storm.trident.operation.TridentOperationContext;
  import storm.trident.tuple.ComboList;
  import storm.trident.tuple.TridentTuple;
  import storm.trident.tuple.TridentTupleView;
  import storm.trident.tuple.TridentTupleView.ProjectionFactory;
  
  public class ChainedAggregatorImpl implements Aggregator<ChainedResult> {
      Aggregator[] _aggs;
      ProjectionFactory[] _inputFactories;
      ComboList.Factory _fact;
      Fields[] _inputFields;
  
      public ChainedAggregatorImpl(Aggregator[] aggs, Fields[] inputFields, ComboList.Factory fact) {
          _aggs = aggs;
          _inputFields = inputFields;
          _fact = fact;
          if (_aggs.length != _inputFields.length) {
              throw new IllegalArgumentException("Require input fields for each aggregator");
          }
      }
  
      public void prepare(Map conf, TridentOperationContext context) {
          _inputFactories = new ProjectionFactory[_inputFields.length];
          for (int i = 0; i < _inputFields.length; i++) {
              _inputFactories[i] = context.makeProjectionFactory(_inputFields[i]);
              _aggs[i].prepare(conf, new TridentOperationContext(context, _inputFactories[i]));
          }
      }
  
      public ChainedResult init(Object batchId, TridentCollector collector) {
          ChainedResult initted = new ChainedResult(collector, _aggs.length);
          for (int i = 0; i < _aggs.length; i++) {
              initted.objs[i] = _aggs[i].init(batchId, initted.collectors[i]);
          }
          return initted;
      }
  
      public void aggregate(ChainedResult val, TridentTuple tuple, TridentCollector collector) {
          val.setFollowThroughCollector(collector);
          for (int i = 0; i < _aggs.length; i++) {
              TridentTuple projected = _inputFactories[i].create((TridentTupleView) tuple);
              _aggs[i].aggregate(val.objs[i], projected, val.collectors[i]);
          }
      }
  
      public void complete(ChainedResult val, TridentCollector collector) {
          val.setFollowThroughCollector(collector);
          for (int i = 0; i < _aggs.length; i++) {
              _aggs[i].complete(val.objs[i], val.collectors[i]);
          }
          if (_aggs.length > 1) { // otherwise, tuples were emitted directly
              int[] indices = new int[val.collectors.length];
              for (int i = 0; i < indices.length; i++) {
                  indices[i] = 0;
              }
              boolean keepGoing = true;
              // emit cross-join of all emitted tuples
              while (keepGoing) {
                  List[] combined = new List[_aggs.length];
                  for (int i = 0; i < _aggs.length; i++) {
                      CaptureCollector capturer = (CaptureCollector) val.collectors[i];
                      combined[i] = capturer.captured.get(indices[i]);
                  }
                  collector.emit(_fact.create(combined));
                  keepGoing = increment(val.collectors, indices, indices.length - 1);
              }
          }
      }
  
      // return false if can't increment anymore
      private boolean increment(TridentCollector[] lengths, int[] indices, int j) {
          if (j == -1)
              return false;
          indices[j]++;
          CaptureCollector capturer = (CaptureCollector) lengths[j];
          if (indices[j] >= capturer.captured.size()) {
              indices[j] = 0;
              return increment(lengths, indices, j - 1);
          }
          return true;
      }
  
      public void cleanup() {
          for (Aggregator a : _aggs) {
              a.cleanup();
          }
      }
  }
  