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.fnexecution.translation;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkArgument;
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkNotNull;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import org.apache.beam.model.pipeline.v1.RunnerApi.ExecutableStagePayload.SideInputId;
  import org.apache.beam.runners.fnexecution.state.StateRequestHandler;
  import org.apache.beam.runners.fnexecution.state.StateRequestHandlers.IterableSideInputHandler;
  import org.apache.beam.runners.fnexecution.state.StateRequestHandlers.MultimapSideInputHandler;
  import org.apache.beam.runners.fnexecution.state.StateRequestHandlers.SideInputHandlerFactory;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.KvCoder;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.util.construction.graph.ExecutableStage;
  import org.apache.beam.sdk.util.construction.graph.SideInputReference;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.PCollectionView;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableMap;
  
  /**
   * {@link StateRequestHandler} that uses {@link org.apache.beam.runners.core.SideInputHandler} to
   * access the broadcast state that represents side inputs.
   */
  @SuppressWarnings({
    "rawtypes", // TODO(https://github.com/apache/beam/issues/20447)
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class StreamingSideInputHandlerFactory implements SideInputHandlerFactory {
  
    // Map from side input id to global PCollection id.
    private final Map<SideInputId, PCollectionView<?>> sideInputToCollection;
    private final org.apache.beam.runners.core.SideInputHandler runnerHandler;
  
    /**
     * Creates a new state handler for the given stage. Note that this requires a traversal of the
     * stage itself, so this should only be called once per stage rather than once per bundle.
     */
    public static StreamingSideInputHandlerFactory forStage(
        ExecutableStage stage,
        Map<SideInputId, PCollectionView<?>> viewMapping,
        org.apache.beam.runners.core.SideInputHandler runnerHandler) {
      ImmutableMap.Builder<SideInputId, PCollectionView<?>> sideInputBuilder = ImmutableMap.builder();
      for (SideInputReference sideInput : stage.getSideInputs()) {
        SideInputId sideInputId =
            SideInputId.newBuilder()
                .setTransformId(sideInput.transform().getId())
                .setLocalName(sideInput.localName())
                .build();
        sideInputBuilder.put(
            sideInputId,
            checkNotNull(
                viewMapping.get(sideInputId),
                "No side input for %s/%s",
                sideInputId.getTransformId(),
                sideInputId.getLocalName()));
      }
  
      StreamingSideInputHandlerFactory factory =
          new StreamingSideInputHandlerFactory(sideInputBuilder.build(), runnerHandler);
      return factory;
    }
  
    private StreamingSideInputHandlerFactory(
        Map<SideInputId, PCollectionView<?>> sideInputToCollection,
        org.apache.beam.runners.core.SideInputHandler runnerHandler) {
      this.sideInputToCollection = sideInputToCollection;
      this.runnerHandler = runnerHandler;
    }
  
    @Override
    public <V, W extends BoundedWindow> IterableSideInputHandler<V, W> forIterableSideInput(
        String transformId, String sideInputId, Coder<V> elementCoder, Coder<W> windowCoder) {
  
      PCollectionView collectionNode =
          sideInputToCollection.get(
              SideInputId.newBuilder().setTransformId(transformId).setLocalName(sideInputId).build());
      checkArgument(collectionNode != null, "No side input for %s/%s", transformId, sideInputId);
  
      return new IterableSideInputHandler<V, W>() {
        @Override
        public Iterable<V> get(W window) {
          return checkNotNull(
              (Iterable<V>) runnerHandler.getIterable(collectionNode, window),
              "Element processed by SDK before side input is ready");
        }
  
        @Override
        public Coder<V> elementCoder() {
          return elementCoder;
        }
      };
    }
  
    @Override
    public <K, V, W extends BoundedWindow> MultimapSideInputHandler<K, V, W> forMultimapSideInput(
        String transformId, String sideInputId, KvCoder<K, V> elementCoder, Coder<W> windowCoder) {
  
      PCollectionView collectionNode =
          sideInputToCollection.get(
              SideInputId.newBuilder().setTransformId(transformId).setLocalName(sideInputId).build());
      checkArgument(collectionNode != null, "No side input for %s/%s", transformId, sideInputId);
  
      return new MultimapSideInputHandler<K, V, W>() {
        @Override
        public Iterable<V> get(K key, W window) {
          Iterable<KV<K, V>> values =
              (Iterable<KV<K, V>>) runnerHandler.getIterable(collectionNode, window);
          Object structuralK = keyCoder().structuralValue(key);
          ArrayList<V> result = new ArrayList<>();
          // find values for the given key
          for (KV<K, V> kv : values) {
            if (structuralK.equals(keyCoder().structuralValue(kv.getKey()))) {
              result.add(kv.getValue());
            }
          }
          return Collections.unmodifiableList(result);
        }
  
        @Override
        public Iterable<K> get(W window) {
          Iterable<KV<K, V>> values =
              (Iterable<KV<K, V>>) runnerHandler.getIterable(collectionNode, window);
  
          Map<Object, K> result = new HashMap<>();
          // find all keys
          for (KV<K, V> kv : values) {
            result.putIfAbsent(keyCoder().structuralValue(kv.getKey()), kv.getKey());
          }
          return Collections.unmodifiableCollection(result.values());
        }
  
        @Override
        public Coder<K> keyCoder() {
          return elementCoder.getKeyCoder();
        }
  
        @Override
        public Coder<V> valueCoder() {
          return elementCoder.getValueCoder();
        }
      };
    }
  }
  