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.dataflow.worker;
  
  import java.util.Collection;
  import java.util.Map;
  import org.apache.beam.runners.core.SideInputReader;
  import org.apache.beam.sdk.Pipeline;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.transforms.Materialization;
  import org.apache.beam.sdk.transforms.Materializations;
  import org.apache.beam.sdk.transforms.Materializations.MultimapView;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.transforms.ViewFn;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.transforms.windowing.WindowFn;
  import org.apache.beam.sdk.transforms.windowing.WindowMappingFn;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.PCollectionView;
  import org.apache.beam.sdk.values.PInput;
  import org.apache.beam.sdk.values.PValue;
  import org.apache.beam.sdk.values.TupleTag;
  import org.apache.beam.sdk.values.TypeDescriptor;
  import org.apache.beam.sdk.values.WindowedValues.FullWindowedValueCoder;
  import org.apache.beam.sdk.values.WindowingStrategy;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * The minimal amount of information required to create and use a {@link SideInputReader} when using
   * the portability framework within the Dataflow Runner harness.
   *
   * <p>Note that this is being used to satisfy type constraints for {@link SideInputReader} used
   * throughout the Dataflow Runner harness and only supports returning the tag, the coder, the
   * materialization, and the window coder. All other methods throw {@link
   * UnsupportedOperationException}.
   *
   * <p>TODO: Migrate to a runner only specific concept of a side input to be used with {@link
   * SideInputReader}s.
   */
  @SuppressWarnings({
    "rawtypes" // TODO(https://github.com/apache/beam/issues/20447)
  })
  public class DataflowPortabilityPCollectionView<K, V, W extends BoundedWindow>
      implements PCollectionView<MultimapView<K, V>> {
  
    public static <K, V> PCollectionView<MultimapView<K, V>> with(
        TupleTag<KV<K, V>> tag, FullWindowedValueCoder<KV<K, V>> coder) {
      return new DataflowPortabilityPCollectionView(tag, coder);
    }
  
    private final TupleTag<KV<K, V>> tag;
    private final FullWindowedValueCoder<KV<K, V>> coder;
  
    private DataflowPortabilityPCollectionView(
        TupleTag<KV<K, V>> tag, FullWindowedValueCoder<KV<K, V>> coder) {
      this.tag = tag;
      this.coder = coder;
    }
  
    @Override
    public @Nullable PCollection<?> getPCollection() {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public TupleTag<KV<K, V>> getTagInternal() {
      return tag;
    }
  
    @Override
    public ViewFn<?, MultimapView<K, V>> getViewFn() {
      return (ViewFn) PortabilityViewFn.INSTANCE;
    }
  
    /**
     * A minimal type {@link ViewFn} that satisfies requirements to be used when executing portable
     * pipelines.
     */
    public static class PortabilityViewFn<K, V>
        extends ViewFn<MultimapView<K, V>, MultimapView<K, V>> {
      private static final PortabilityViewFn<Object, Object> INSTANCE = new PortabilityViewFn<>();
  
      // prevent instantiation
      private PortabilityViewFn() {}
  
      @Override
      public Materialization<MultimapView<K, V>> getMaterialization() {
        return Materializations.multimap();
      }
  
      @Override
      public MultimapView<K, V> apply(MultimapView<K, V> o) {
        return o;
      }
  
      @Override
      public TypeDescriptor<MultimapView<K, V>> getTypeDescriptor() {
        throw new UnsupportedOperationException();
      }
    };
  
    @Override
    public WindowMappingFn<?> getWindowMappingFn() {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public WindowingStrategy<KV<K, V>, W> getWindowingStrategyInternal() {
      return WindowingStrategy.of(
          new WindowFn<KV<K, V>, W>() {
            @Override
            public Collection<W> assignWindows(AssignContext c) throws Exception {
              throw new UnsupportedOperationException();
            }
  
            @Override
            public void mergeWindows(MergeContext c) throws Exception {
              throw new UnsupportedOperationException();
            }
  
            @Override
            public boolean isCompatible(WindowFn<?, ?> other) {
              throw new UnsupportedOperationException();
            }
  
            @Override
            public Coder<W> windowCoder() {
              return (Coder) coder.getWindowCoder();
            }
  
            @Override
            public WindowMappingFn<W> getDefaultWindowMappingFn() {
              throw new UnsupportedOperationException();
            }
          });
    }
  
    @Override
    public Coder<?> getCoderInternal() {
      return coder.getValueCoder();
    }
  
    @Override
    public String getName() {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public Pipeline getPipeline() {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public Map<TupleTag<?>, PValue> expand() {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public void finishSpecifyingOutput(
        String transformName, PInput input, PTransform<?, ?> transform) {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public void finishSpecifying(PInput upstreamInput, PTransform<?, ?> upstreamTransform) {
      throw new UnsupportedOperationException();
    }
  }
  