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.test.yaml.resolver;
  
  import au.csiro.pathling.fhirpath.context.ResourceResolver;
  import au.csiro.pathling.fhirpath.definition.defaults.DefaultDefinitionContext;
  import au.csiro.pathling.fhirpath.definition.defaults.DefaultResourceDefinition;
  import au.csiro.pathling.fhirpath.definition.defaults.DefaultResourceTag;
  import au.csiro.pathling.fhirpath.execution.DefaultResourceResolver;
  import java.util.function.Function;
  import lombok.AllArgsConstructor;
  import lombok.Value;
  
  /**
   * Factory for creating empty resource resolvers. This implementation provides a resolver that
   * returns an empty DataFrame, useful for testing expressions that don't require input data.
   */
  @Value
  @AllArgsConstructor(access = lombok.AccessLevel.PRIVATE)
  public class EmptyResolverFactory implements Function<RuntimeContext, ResourceResolver> {
  
  
    // singleton
    private static final EmptyResolverFactory INSTANCE = new EmptyResolverFactory();
  
    public static EmptyResolverFactory getInstance() {
      return INSTANCE;
    }
  
    @Override
    public ResourceResolver apply(final RuntimeContext runtimeContext) {
  
      final DefaultResourceTag subjectResourceTag = DefaultResourceTag.of("Empty");
      return DefaultResourceResolver.of(
          subjectResourceTag,
          DefaultDefinitionContext.of(DefaultResourceDefinition.of(subjectResourceTag)),
          runtimeContext.getSpark().emptyDataFrame()
      );
    }
  }
  