| /* |
| * 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.nemo.common.ir.vertex.transform; |
| |
| import org.apache.nemo.common.Pair; |
| import org.apache.nemo.common.ir.OutputCollector; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.function.BiFunction; |
| |
| /** |
| * A {@link Transform} that aggregates statistics generated by the {@link MessageBarrierTransform}. |
| * |
| * @param <K> input key type. |
| * @param <V> input value type. |
| * @param <O> output type. |
| */ |
| public final class MessageAggregatorTransform<K, V, O> extends NoWatermarkEmitTransform<Pair<K, V>, O> { |
| private static final Logger LOG = LoggerFactory.getLogger(MessageAggregatorTransform.class.getName()); |
| private OutputCollector<O> outputCollector; |
| private O aggregatedDynOptData; |
| private final BiFunction<Pair<K, V>, O, O> dynOptDataAggregator; |
| |
| /** |
| * Default constructor. |
| * |
| * @param aggregatedDynOptData per-stage aggregated dynamic optimization data. |
| * @param dynOptDataAggregator aggregator to use. |
| */ |
| public MessageAggregatorTransform(final O aggregatedDynOptData, |
| final BiFunction<Pair<K, V>, O, O> dynOptDataAggregator) { |
| this.aggregatedDynOptData = aggregatedDynOptData; |
| this.dynOptDataAggregator = dynOptDataAggregator; |
| } |
| |
| @Override |
| public void prepare(final Context context, final OutputCollector<O> oc) { |
| this.outputCollector = oc; |
| } |
| |
| @Override |
| public void onData(final Pair<K, V> element) { |
| aggregatedDynOptData = dynOptDataAggregator.apply(element, aggregatedDynOptData); |
| } |
| |
| @Override |
| public void close() { |
| outputCollector.emit(aggregatedDynOptData); |
| } |
| |
| @Override |
| public String toString() { |
| final StringBuilder sb = new StringBuilder(); |
| sb.append(MessageAggregatorTransform.class); |
| sb.append(":"); |
| sb.append(super.toString()); |
| return sb.toString(); |
| } |
| } |