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.sdk.util.construction.graph;
  
  import com.google.auto.value.AutoValue;
  import java.io.IOException;
  import org.apache.beam.model.pipeline.v1.RunnerApi;
  import org.apache.beam.model.pipeline.v1.RunnerApi.ExecutableStagePayload.UserStateId;
  import org.apache.beam.model.pipeline.v1.RunnerApi.PTransform;
  import org.apache.beam.sdk.util.construction.ParDoTranslation;
  import org.apache.beam.sdk.util.construction.graph.PipelineNode.PCollectionNode;
  import org.apache.beam.sdk.util.construction.graph.PipelineNode.PTransformNode;
  
  /**
   * A reference to user state. This includes the PTransform that references the user state as well as
   * the local name. Both are necessary in order to fully resolve user state.
   */
  @AutoValue
  public abstract class UserStateReference {
  
    /** Create a user state reference. */
    public static UserStateReference of(
        PTransformNode transform, String localName, PCollectionNode collection) {
      return new AutoValue_UserStateReference(transform, localName, collection);
    }
  
    /** Create a user state reference from a UserStateId proto and components. */
    public static UserStateReference fromUserStateId(
        UserStateId userStateId, RunnerApi.Components components) {
      PTransform transform = components.getTransformsOrThrow(userStateId.getTransformId());
      String mainInputCollectionId;
      try {
        mainInputCollectionId =
            transform.getInputsOrThrow(ParDoTranslation.getMainInputName(transform));
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
      return UserStateReference.of(
          PipelineNode.pTransform(userStateId.getTransformId(), transform),
          userStateId.getLocalName(),
          PipelineNode.pCollection(
              mainInputCollectionId, components.getPcollectionsOrThrow(mainInputCollectionId)));
    }
  
    /** The id of the PTransform that uses this user state. */
    public abstract PTransformNode transform();
    /** The local name the referencing PTransform uses to refer to this user state. */
    public abstract String localName();
    /** The PCollection that represents the input to the PTransform. */
    public abstract PCollectionNode collection();
  }
  