| /** |
| * 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.heron.streamlet.impl.streamlets; |
| |
| import java.util.Set; |
| |
| import org.apache.heron.api.topology.TopologyBuilder; |
| import org.apache.heron.streamlet.KeyValue; |
| import org.apache.heron.streamlet.SerializableBinaryOperator; |
| import org.apache.heron.streamlet.SerializableFunction; |
| import org.apache.heron.streamlet.impl.StreamletImpl; |
| import org.apache.heron.streamlet.impl.groupings.ReduceByKeyAndWindowCustomGrouping; |
| import org.apache.heron.streamlet.impl.operators.ReduceByKeyOperator; |
| |
| /** |
| * ReduceByKeyStreamlet represents a KVStreamlet that is the result of |
| * applying user supplied reduceFn on all elements. |
| * ReduceByKeyAndWindowStreamlet's elements are of KeyValue type where the key is |
| * KeyWindowInfo<K> type and the value is of type T. |
| */ |
| public class ReduceByKeyStreamlet<R, K, T> extends StreamletImpl<KeyValue<K, T>> { |
| private StreamletImpl<R> parent; |
| private SerializableFunction<R, K> keyExtractor; |
| private SerializableFunction<R, T> valueExtractor; |
| private SerializableBinaryOperator<T> reduceFn; |
| |
| public ReduceByKeyStreamlet(StreamletImpl<R> parent, |
| SerializableFunction<R, K> keyExtractor, |
| SerializableFunction<R, T> valueExtractor, |
| SerializableBinaryOperator<T> reduceFn) { |
| this.parent = parent; |
| this.keyExtractor = keyExtractor; |
| this.valueExtractor = valueExtractor; |
| this.reduceFn = reduceFn; |
| setNumPartitions(parent.getNumPartitions()); |
| } |
| |
| @Override |
| public boolean doBuild(TopologyBuilder bldr, Set<String> stageNames) { |
| setDefaultNameIfNone(StreamletNamePrefix.REDUCE, stageNames); |
| ReduceByKeyOperator<R, K, T> bolt = |
| new ReduceByKeyOperator<R, K, T>(keyExtractor, valueExtractor, reduceFn); |
| bldr.setBolt(getName(), bolt, getNumPartitions()) |
| .customGrouping(parent.getName(), parent.getStreamId(), |
| new ReduceByKeyAndWindowCustomGrouping<R, K>(keyExtractor)); |
| return true; |
| } |
| } |