| /** |
| * 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 java.io.Serializable; |
| import java.util.Map; |
| import storm.trident.operation.Aggregator; |
| import storm.trident.operation.TridentCollector; |
| import storm.trident.operation.TridentOperationContext; |
| import storm.trident.operation.impl.SingleEmitAggregator.SingleEmitState; |
| import storm.trident.tuple.TridentTuple; |
| |
| public class SingleEmitAggregator implements Aggregator<SingleEmitState> { |
| public static interface BatchToPartition extends Serializable { |
| int partitionIndex(Object batchId, int numPartitions); |
| } |
| |
| static class SingleEmitState { |
| boolean received = false; |
| Object state; |
| Object batchId; |
| |
| public SingleEmitState(Object batchId) { |
| this.batchId = batchId; |
| } |
| } |
| |
| Aggregator _agg; |
| BatchToPartition _batchToPartition; |
| |
| public SingleEmitAggregator(Aggregator agg, BatchToPartition batchToPartition) { |
| _agg = agg; |
| _batchToPartition = batchToPartition; |
| } |
| |
| @Override |
| public SingleEmitState init(Object batchId, TridentCollector collector) { |
| return new SingleEmitState(batchId); |
| } |
| |
| @Override |
| public void aggregate(SingleEmitState val, TridentTuple tuple, TridentCollector collector) { |
| if (!val.received) { |
| val.state = _agg.init(val.batchId, collector); |
| val.received = true; |
| } |
| _agg.aggregate(val.state, tuple, collector); |
| } |
| |
| @Override |
| public void complete(SingleEmitState val, TridentCollector collector) { |
| if (!val.received) { |
| if (this.myPartitionIndex == _batchToPartition.partitionIndex(val.batchId, this.totalPartitions)) { |
| val.state = _agg.init(val.batchId, collector); |
| _agg.complete(val.state, collector); |
| } |
| } else { |
| _agg.complete(val.state, collector); |
| } |
| } |
| |
| int myPartitionIndex; |
| int totalPartitions; |
| |
| @Override |
| public void prepare(Map conf, TridentOperationContext context) { |
| _agg.prepare(conf, context); |
| this.myPartitionIndex = context.getPartitionIndex(); |
| this.totalPartitions = context.numPartitions(); |
| } |
| |
| @Override |
| public void cleanup() { |
| _agg.cleanup(); |
| } |
| |
| } |