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;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkState;
  
  import org.apache.beam.model.pipeline.v1.RunnerApi;
  import org.apache.beam.model.pipeline.v1.RunnerApi.StandardSideInputTypes;
  import org.apache.beam.sdk.annotations.Internal;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * <b><i>For internal use only; no backwards-compatibility guarantees.</i></b>
   *
   * <p>Utility methods for constructing known {@link Materialization materializations} for a {@link
   * ViewFn}.
   */
  @Internal
  public class Materializations {
    /**
     * The URN for a {@link Materialization} where the primitive view type is an iterable of fully
     * specified windowed values.
     */
    public static final String ITERABLE_MATERIALIZATION_URN = "beam:side_input:iterable:v1";
  
    static {
      // Use a constant above so that they can be used in switch case statements and validate
      // that the constant hasn't changed from the proto definition on class load.
      checkState(
          ITERABLE_MATERIALIZATION_URN.equals(
              StandardSideInputTypes.Enum.ITERABLE
                  .getValueDescriptor()
                  .getOptions()
                  .getExtension(RunnerApi.beamUrn)),
          "Expected %s to match proto constant but found %s.",
          ITERABLE_MATERIALIZATION_URN,
          StandardSideInputTypes.Enum.ITERABLE
              .getValueDescriptor()
              .getOptions()
              .getExtension(RunnerApi.beamUrn));
    }
  
    /**
     * The URN for a {@link Materialization} where the primitive view type is a multimap of fully
     * specified windowed values.
     */
    public static final String MULTIMAP_MATERIALIZATION_URN = "beam:side_input:multimap:v1";
  
    static {
      // Use a constant above so that they can be used in switch case statements and validate
      // that the constant hasn't changed from the proto definition on class load.
      checkState(
          MULTIMAP_MATERIALIZATION_URN.equals(
              StandardSideInputTypes.Enum.MULTIMAP
                  .getValueDescriptor()
                  .getOptions()
                  .getExtension(RunnerApi.beamUrn)),
          "Expected %s to match proto constant but found %s.",
          MULTIMAP_MATERIALIZATION_URN,
          StandardSideInputTypes.Enum.MULTIMAP
              .getValueDescriptor()
              .getOptions()
              .getExtension(RunnerApi.beamUrn));
    }
  
    /**
     * Represents the {@code PrimitiveViewT} supplied to the {@link ViewFn} when it declares to use
     * the {@link Materializations#ITERABLE_MATERIALIZATION_URN iterable materialization}.
     *
     * @param <V>
     */
    public interface IterableView<V> {
      /** Returns an iterable for all values. */
      Iterable<V> get();
    }
  
    /**
     * Represents the {@code PrimitiveViewT} supplied to the {@link ViewFn} when it declares to use
     * the {@link Materializations#MULTIMAP_MATERIALIZATION_URN multimap materialization}.
     */
    public interface MultimapView<K, V> {
      /** Returns an iterable of all keys. */
      Iterable<K> get();
  
      /** Returns an iterable of all the values for the specified key. */
      Iterable<V> get(@Nullable K k);
    }
  
    /**
     * <b><i>For internal use only; no backwards-compatibility guarantees.</i></b>
     *
     * <p>A {@link Materialization} where the primitive view type is a multimap with fully specified
     * windowed values.
     */
    @Internal
    public static <K, V> Materialization<MultimapView<K, V>> multimap() {
      return new Materialization<MultimapView<K, V>>() {
        @Override
        public String getUrn() {
          return MULTIMAP_MATERIALIZATION_URN;
        }
      };
    }
  
    /**
     * <b><i>For internal use only; no backwards-compatibility guarantees.</i></b>
     *
     * <p>A {@link Materialization} where the primitive view type is an iterable with fully specifed
     * windowed values.
     */
    @Internal
    public static <V> Materialization<IterableView<V>> iterable() {
      return new Materialization<IterableView<V>>() {
        @Override
        public String getUrn() {
          return ITERABLE_MATERIALIZATION_URN;
        }
      };
    }
  }
  