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.extensions.euphoria.core.client.operator;
  
  import org.apache.beam.sdk.extensions.euphoria.core.client.operator.base.Operator;
  import org.apache.beam.sdk.extensions.euphoria.core.translate.OperatorTransform;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.PCollectionList;
  import org.apache.beam.sdk.values.TypeDescriptor;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * Internal operator used to extract values from keyed output.
   *
   * @param <InputT> input type
   * @param <KeyT> key type
   * @param <OutputT> output type
   */
  class OutputValues<InputT, KeyT, OutputT> extends Operator<OutputT>
      implements CompositeOperator<InputT, OutputT> {
  
    private final Operator<KV<KeyT, OutputT>> keyedOperator;
  
    OutputValues(
        @Nullable String name,
        @Nullable TypeDescriptor<OutputT> outputType,
        Operator<KV<KeyT, OutputT>> keyedOperator) {
      super(name, outputType);
      this.keyedOperator = keyedOperator;
    }
  
    @Override
    public PCollection<OutputT> expand(PCollectionList<InputT> inputs) {
      final PCollection<KV<KeyT, OutputT>> keyedOutput =
          OperatorTransform.apply(keyedOperator, inputs);
      return MapElements.named("ExtractValues")
          .of(keyedOutput)
          .using(KV::getValue, getOutputType().orElse(null))
          .output();
    }
  }
  