content: /*
   * 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.dataflow.worker.apiary;
  
  import com.google.api.services.dataflow.model.MapTask;
  import com.google.api.services.dataflow.model.MultiOutputInfo;
  import com.google.api.services.dataflow.model.ParDoInstruction;
  import com.google.api.services.dataflow.model.ParallelInstruction;
  import java.util.List;
  import java.util.function.Function;
  import org.apache.beam.sdk.fn.IdGenerator;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  
  /**
   * {@link ParDoInstruction}s are meant to always have {@link MultiOutputInfo}s which give names to
   * the outputs. This function fixes {@link ParDoInstruction}s by filling in a default {@link
   * MultiOutputInfo} with an output tag using the supplied id generator. Note that the id generator
   * should supply ids outside the ids used within the {@link MapTask} to prevent collisions.
   */
  public class FixMultiOutputInfosOnParDoInstructions implements Function<MapTask, MapTask> {
    private final IdGenerator idGenerator;
  
    public FixMultiOutputInfosOnParDoInstructions(IdGenerator idGenerator) {
      this.idGenerator = idGenerator;
    }
  
    @Override
    public MapTask apply(MapTask input) {
      for (ParallelInstruction instruction : Apiary.listOrEmpty(input.getInstructions())) {
        ParDoInstruction parDoInstruction = instruction.getParDo();
        if (parDoInstruction != null) {
          int numOutputs = Apiary.intOrZero(parDoInstruction.getNumOutputs());
          List<MultiOutputInfo> multiOutputInfos =
              Apiary.listOrEmpty(parDoInstruction.getMultiOutputInfos());
          if (numOutputs != Apiary.listOrEmpty(instruction.getParDo().getMultiOutputInfos()).size()) {
            if (numOutputs == 1) {
              parDoInstruction.setMultiOutputInfos(
                  ImmutableList.of(new MultiOutputInfo().setTag(idGenerator.getId())));
            } else {
              throw new IllegalArgumentException(
                  String.format(
                      "Invalid ParDoInstruction %s, %d outputs specified, found %s tags.",
                      instruction.getSystemName(), numOutputs, multiOutputInfos));
            }
          }
        }
      }
      return input;
    }
  }
  