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.transforms.display;
  
  import java.util.Objects;
  import java.util.Set;
  import org.apache.beam.sdk.Pipeline;
  import org.apache.beam.sdk.PipelineRunner;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.VoidCoder;
  import org.apache.beam.sdk.options.PipelineOptions;
  import org.apache.beam.sdk.runners.TransformHierarchy;
  import org.apache.beam.sdk.testing.TestPipeline;
  import org.apache.beam.sdk.transforms.Create;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.values.PBegin;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.POutput;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.Sets;
  
  /**
   * Test utilities to evaluate the {@link DisplayData} in the context of a {@link PipelineRunner}.
   */
  public class DisplayDataEvaluator {
    private final PipelineOptions options;
  
    /**
     * Create a new {@link DisplayDataEvaluator} using options returned from {@link
     * #getDefaultOptions()}.
     */
    public static DisplayDataEvaluator create() {
      return create(getDefaultOptions());
    }
  
    /** Create a new {@link DisplayDataEvaluator} using the specified {@link PipelineOptions}. */
    public static DisplayDataEvaluator create(PipelineOptions pipelineOptions) {
      return new DisplayDataEvaluator(pipelineOptions);
    }
  
    /** The default {@link PipelineOptions} which will be used by {@link #create()}. */
    public static PipelineOptions getDefaultOptions() {
      return TestPipeline.testingPipelineOptions();
    }
  
    private DisplayDataEvaluator(PipelineOptions options) {
      this.options = options;
    }
  
    /**
     * Traverse the specified {@link PTransform}, collecting {@link DisplayData} registered on the
     * inner primitive {@link PTransform PTransforms}.
     *
     * @return the set of {@link DisplayData} for primitive {@link PTransform PTransforms}.
     */
    public <InputT> Set<DisplayData> displayDataForPrimitiveTransforms(
        final PTransform<? super PCollection<InputT>, ? extends POutput> root) {
      return displayDataForPrimitiveTransforms(root, null);
    }
  
    /**
     * Traverse the specified {@link PTransform}, collecting {@link DisplayData} registered on the
     * inner primitive {@link PTransform PTransforms}.
     *
     * @param root The root {@link PTransform} to traverse
     * @param inputCoder The coder to set for the {@link PTransform} input, or null to infer the
     *     default coder.
     * @return the set of {@link DisplayData} for primitive {@link PTransform PTransforms}.
     */
    public <InputT> Set<DisplayData> displayDataForPrimitiveTransforms(
        final PTransform<? super PCollection<InputT>, ? extends POutput> root,
        Coder<InputT> inputCoder) {
  
      Create.Values<InputT> input;
      if (inputCoder != null) {
        input = Create.empty(inputCoder);
      } else {
        // These types don't actually work, but the pipeline will never be run
        input = (Create.Values<InputT>) Create.empty(VoidCoder.of());
      }
  
      Pipeline pipeline = Pipeline.create(options);
      pipeline.apply("Input", input).apply("Transform", root);
  
      return displayDataForPipeline(pipeline, root);
    }
  
    /**
     * Traverse the specified source {@link PTransform}, collecting {@link DisplayData} registered on
     * the inner primitive {@link PTransform PTransforms}.
     *
     * @param root The source root {@link PTransform} to traverse
     * @return the set of {@link DisplayData} for primitive source {@link PTransform PTransforms}.
     */
    public Set<DisplayData> displayDataForPrimitiveSourceTransforms(
        final PTransform<? super PBegin, ? extends POutput> root) {
      Pipeline pipeline = Pipeline.create(options);
      pipeline.apply("SourceTransform", root);
  
      return displayDataForPipeline(pipeline, root);
    }
  
    private static Set<DisplayData> displayDataForPipeline(Pipeline pipeline, PTransform<?, ?> root) {
      PrimitiveDisplayDataPTransformVisitor visitor = new PrimitiveDisplayDataPTransformVisitor(root);
      pipeline.traverseTopologically(visitor);
      return visitor.getPrimitivesDisplayData();
    }
  
    /**
     * Visits {@link PTransform PTransforms} in a pipeline, and collects {@link DisplayData} for each
     * primitive transform under a given composite root.
     */
    private static class PrimitiveDisplayDataPTransformVisitor
        extends Pipeline.PipelineVisitor.Defaults {
      private final PTransform<?, ?> root;
      private final Set<DisplayData> displayData;
      private boolean inCompositeRoot = false;
  
      PrimitiveDisplayDataPTransformVisitor(PTransform<?, ?> root) {
        this.root = root;
        this.displayData = Sets.newHashSet();
      }
  
      Set<DisplayData> getPrimitivesDisplayData() {
        return displayData;
      }
  
      @Override
      public CompositeBehavior enterCompositeTransform(TransformHierarchy.Node node) {
        if (Objects.equals(root, node.getTransform())) {
          inCompositeRoot = true;
        }
  
        return CompositeBehavior.ENTER_TRANSFORM;
      }
  
      @Override
      public void leaveCompositeTransform(TransformHierarchy.Node node) {
        if (Objects.equals(root, node.getTransform())) {
          inCompositeRoot = false;
        }
      }
  
      @Override
      public void visitPrimitiveTransform(TransformHierarchy.Node node) {
        if (inCompositeRoot || Objects.equals(root, node.getTransform())) {
          displayData.add(DisplayData.from(node.getTransform()));
        }
      }
    }
  }
  