| /** |
| * 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.SerializableFunction; |
| import org.apache.heron.streamlet.impl.StreamletImpl; |
| import org.apache.heron.streamlet.impl.operators.FlatMapOperator; |
| |
| /** |
| * FlatMapStreamlet represents a Streamlet that is made up of applying the user |
| * supplied flatMap function to each element of the parent streamlet and flattening |
| * out the result. |
| */ |
| public class FlatMapStreamlet<R, T> extends StreamletImpl<T> { |
| private StreamletImpl<R> parent; |
| private SerializableFunction<? super R, ? extends Iterable<? extends T>> flatMapFn; |
| |
| public FlatMapStreamlet(StreamletImpl<R> parent, |
| SerializableFunction<? super R, |
| ? extends Iterable<? extends T>> flatMapFn) { |
| this.parent = parent; |
| this.flatMapFn = flatMapFn; |
| setNumPartitions(parent.getNumPartitions()); |
| } |
| |
| @Override |
| public boolean doBuild(TopologyBuilder bldr, Set<String> stageNames) { |
| setDefaultNameIfNone(StreamletNamePrefix.FLATMAP, stageNames); |
| bldr.setBolt(getName(), new FlatMapOperator<R, T>(flatMapFn), |
| getNumPartitions()).shuffleGrouping(parent.getName(), parent.getStreamId()); |
| return true; |
| } |
| } |