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.spark.util;
  
  import java.util.concurrent.ExecutionException;
  import org.apache.beam.runners.core.SideInputReader;
  import org.apache.beam.runners.spark.util.SideInputStorage.Key;
  import org.apache.beam.runners.spark.util.SideInputStorage.Value;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.values.PCollectionView;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.cache.Cache;
  import org.apache.spark.util.SizeEstimator;
  import org.checkerframework.checker.nullness.qual.Nullable;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /** {@link SideInputReader} that caches materialized views. */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class CachedSideInputReader implements SideInputReader {
  
    private static final Logger LOG = LoggerFactory.getLogger(CachedSideInputReader.class);
  
    /**
     * Create a new cached {@link SideInputReader}.
     *
     * @param delegate wrapped reader
     * @return cached reader
     */
    public static CachedSideInputReader of(SideInputReader delegate) {
      return new CachedSideInputReader(delegate);
    }
  
    /** Wrapped {@link SideInputReader} which results will be cached. */
    private final SideInputReader delegate;
  
    private CachedSideInputReader(SideInputReader delegate) {
      this.delegate = delegate;
    }
  
    @Override
    public <T> @Nullable T get(PCollectionView<T> view, BoundedWindow window) {
      @SuppressWarnings("unchecked")
      final Cache<Key<T>, Value<T>> materializedCasted =
          (Cache) SideInputStorage.getMaterializedSideInputs();
  
      Key<T> sideInputKey = new Key<>(view, window);
  
      try {
        Value<T> cachedResult =
            materializedCasted.get(
                sideInputKey,
                () -> {
                  final T result = delegate.get(view, window);
                  LOG.debug(
                      "Caching de-serialized side input for {} of size [{}B] in memory.",
                      sideInputKey,
                      SizeEstimator.estimate(result));
  
                  return new Value<>(result);
                });
        return cachedResult.getValue();
      } catch (ExecutionException e) {
        throw new RuntimeException(e.getCause());
      }
    }
  
    @Override
    public <T> boolean contains(PCollectionView<T> view) {
      return delegate.contains(view);
    }
  
    @Override
    public boolean isEmpty() {
      return delegate.isEmpty();
    }
  }
  