| /* |
| * 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.beam.runners.gearpump.translators; |
| |
| import io.gearpump.streaming.dsl.api.functions.MapFunction; |
| import io.gearpump.streaming.dsl.javaapi.JavaStream; |
| import java.util.HashSet; |
| import java.util.Set; |
| import org.apache.beam.runners.gearpump.translators.io.UnboundedSourceWrapper; |
| import org.apache.beam.runners.gearpump.translators.io.ValuesSource; |
| import org.apache.beam.sdk.coders.StringUtf8Coder; |
| import org.apache.beam.sdk.transforms.Flatten; |
| import org.apache.beam.sdk.values.PCollection; |
| import org.apache.beam.sdk.values.PValue; |
| import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Lists; |
| |
| /** Flatten.FlattenPCollectionList is translated to Gearpump merge function. */ |
| public class FlattenPCollectionsTranslator<T> |
| implements TransformTranslator<Flatten.PCollections<T>> { |
| |
| private static final long serialVersionUID = -5552148802472944759L; |
| |
| @Override |
| public void translate(Flatten.PCollections<T> transform, TranslationContext context) { |
| JavaStream<T> merged = null; |
| Set<PCollection<T>> unique = new HashSet<>(); |
| for (PValue input : context.getInputs().values()) { |
| PCollection<T> collection = (PCollection<T>) input; |
| JavaStream<T> inputStream = context.getInputStream(collection); |
| if (null == merged) { |
| merged = inputStream; |
| } else { |
| // duplicate edges are not allowed in Gearpump graph |
| // so we route through a dummy node |
| if (unique.contains(collection)) { |
| inputStream = inputStream.map(new DummyFunction<>(), "dummy"); |
| } |
| |
| merged = merged.merge(inputStream, 1, transform.getName()); |
| } |
| unique.add(collection); |
| } |
| |
| if (null == merged) { |
| UnboundedSourceWrapper<String, ?> unboundedSourceWrapper = |
| new UnboundedSourceWrapper<>( |
| new ValuesSource<>(Lists.newArrayList("dummy"), StringUtf8Coder.of()), |
| context.getPipelineOptions()); |
| merged = context.getSourceStream(unboundedSourceWrapper); |
| } |
| context.setOutputStream(context.getOutput(), merged); |
| } |
| |
| private static class DummyFunction<T> extends MapFunction<T, T> { |
| |
| private static final long serialVersionUID = 5454396869997290471L; |
| |
| @Override |
| public T map(T t) { |
| return t; |
| } |
| } |
| } |