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 org.apache.beam.model.pipeline.v1.RunnerApi.PCollection;
  import org.apache.beam.model.pipeline.v1.RunnerApi.PTransform;
  
  /** A graph node which contains some pipeline element. */
  public interface PipelineNode {
    static PTransformNode pTransform(String id, PTransform transform) {
      return new AutoValue_PipelineNode_PTransformNode(id, transform);
    }
  
    static PCollectionNode pCollection(String id, PCollection collection) {
      return new AutoValue_PipelineNode_PCollectionNode(id, collection);
    }
  
    String getId();
  
    /** A {@link PipelineNode} which contains a {@link PCollection}. */
    @AutoValue
    abstract class PCollectionNode implements PipelineNode {
      @Override
      public abstract String getId();
  
      public abstract PCollection getPCollection();
    }
  
    /** A {@link PipelineNode} which contains a {@link PTransform}. */
    @AutoValue
    abstract class PTransformNode implements PipelineNode {
      @Override
      public abstract String getId();
  
      public abstract PTransform getTransform();
    }
  }
  