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.samza.translation;
  
  import java.util.List;
  import org.apache.beam.runners.samza.SamzaPipelineOptions;
  import org.apache.beam.runners.samza.runtime.OpMessage;
  import org.apache.beam.runners.samza.util.SamzaCoders;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.runners.TransformHierarchy;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.WindowedValue;
  import org.apache.samza.operators.MessageStream;
  
  /** Translates {@link SamzaPublishView} to a view {@link MessageStream} as side input. */
  class SamzaPublishViewTranslator<ElemT, ViewT>
      implements TransformTranslator<SamzaPublishView<ElemT, ViewT>> {
  
    @Override
    public void translate(
        SamzaPublishView<ElemT, ViewT> transform,
        TransformHierarchy.Node node,
        TranslationContext ctx) {
      final PCollection<List<ElemT>> input = ctx.getInput(transform);
      final MessageStream<OpMessage<Iterable<ElemT>>> inputStream = ctx.getMessageStream(input);
      @SuppressWarnings("unchecked")
      final Coder<WindowedValue<Iterable<ElemT>>> elementCoder = (Coder) SamzaCoders.of(input);
      final String viewId = ctx.getViewId(transform.getView());
  
      final MessageStream<OpMessage<Iterable<ElemT>>> outputStream =
          doTranslate(
              inputStream, elementCoder, ctx.getTransformId(), viewId, ctx.getPipelineOptions());
  
      ctx.registerViewStream(transform.getView(), outputStream);
    }
  
    /**
     * This method is used to translate both native Java PublishView transform as well as portable
     * side input broadcasting into Samza.
     */
    static <ElemT> MessageStream<OpMessage<Iterable<ElemT>>> doTranslate(
        MessageStream<OpMessage<Iterable<ElemT>>> inputStream,
        Coder<WindowedValue<Iterable<ElemT>>> coder,
        String transformId,
        String viewId,
        SamzaPipelineOptions options) {
  
      final MessageStream<WindowedValue<Iterable<ElemT>>> elementStream =
          inputStream
              .filter(msg -> msg.getType() == OpMessage.Type.ELEMENT)
              .map(OpMessage::getElement);
  
      // TODO: once SAMZA-1580 is resolved, this optimization will go directly inside Samza
      final MessageStream<WindowedValue<Iterable<ElemT>>> broadcastStream =
          options.getMaxSourceParallelism() == 1
              ? elementStream
              : elementStream.broadcast(SamzaCoders.toSerde(coder), "view-" + transformId);
  
      return broadcastStream.map(element -> OpMessage.ofSideInput(viewId, element));
    }
  }
  