| /** |
| * 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 org.apache.storm.streams.processors; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| import org.apache.storm.streams.Pair; |
| import org.apache.storm.streams.operations.CombinerAggregator; |
| |
| public class MergeAggregateByKeyProcessor<K, V, A, R> extends BaseProcessor<Pair<K, A>> implements BatchProcessor { |
| protected final CombinerAggregator<V, A, R> aggregator; |
| protected final Map<K, A> state = new HashMap<>(); |
| |
| public MergeAggregateByKeyProcessor(CombinerAggregator<V, A, R> aggregator) { |
| this.aggregator = aggregator; |
| } |
| |
| @Override |
| public void execute(Pair<K, A> input) { |
| K key = input.getFirst(); |
| A val = input.getSecond(); |
| A accumulator = state.get(key); |
| if (accumulator == null) { |
| accumulator = aggregator.init(); |
| } |
| state.put(key, aggregator.merge(accumulator, val)); |
| mayBeForwardAggUpdate(() -> Pair.of(key, aggregator.result(state.get(key)))); |
| } |
| |
| @Override |
| public void finish() { |
| for (Map.Entry<K, A> entry : state.entrySet()) { |
| context.forward(Pair.of(entry.getKey(), aggregator.result(entry.getValue()))); |
| } |
| state.clear(); |
| } |
| |
| } |