content: /*
   * Copyright © 2018-2025 Commonwealth Scientific and Industrial Research
   * Organisation (CSIRO) ABN 41 687 119 230.
   *
   * Licensed 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 au.csiro.pathling.library;
  
  import static java.util.Objects.requireNonNull;
  
  import ca.uhn.fhir.context.FhirVersionEnum;
  import jakarta.annotation.Nonnull;
  import jakarta.annotation.Nullable;
  import java.io.Serial;
  import java.util.Iterator;
  import java.util.stream.Stream;
  import java.util.stream.StreamSupport;
  import org.apache.spark.api.java.function.MapPartitionsFunction;
  import org.hl7.fhir.instance.model.api.IBaseResource;
  
  abstract class EncodeMapPartitions<T extends IBaseResource> implements
      MapPartitionsFunction<String, T> {
  
    @Serial
    private static final long serialVersionUID = -189338116652852324L;
  
    @Nonnull
    protected final FhirVersionEnum fhirVersion;
  
    @Nonnull
    protected final String inputMimeType;
  
    @Nonnull
    protected final Class<T> resourceClass;
  
    protected EncodeMapPartitions(@Nonnull final FhirVersionEnum fhirVersion,
        @Nonnull final String inputMimeType, @Nonnull final Class<T> resourceClass) {
      this.fhirVersion = fhirVersion;
      this.inputMimeType = inputMimeType;
      this.resourceClass = resourceClass;
    }
  
    /**
     * Converts the parsed input resouces to the final stream of requested resources. May include
     * filtering, extracting from bundles etc.
     *
     * @param resources the stream of all input resources
     * @return the stream of desired resources
     */
    @Nonnull
    protected abstract Stream<IBaseResource> processResources(
        @Nonnull final Stream<IBaseResource> resources);
  
    @SuppressWarnings("unchecked")
    @Override
    @Nonnull
    public Iterator<T> call(@Nullable final Iterator<String> iterator) {
      requireNonNull(iterator);
      final ResourceParser parser = ResourceParser.build(fhirVersion, inputMimeType);
  
      final Iterable<String> iterable = () -> iterator;
      final Stream<IBaseResource> parsedResources = StreamSupport.stream(iterable.spliterator(),
              false)
          .map(parser::parse);
      return (Iterator<T>) processResources(parsedResources).iterator();
    }
  }
  