Allow inherited DelegatingConverter to be processed

Related to https://github.com/mapstruct/mapstruct-spring-extensions/issues/101

Hi,

I am trying to modify the annotation processor to support custom Converter interface but I don't know how to process DelegatingConverter by inheritance.

New code in ConverterMapperProcessor:

delegatingConverterDescriptors =
        annotations.stream()
            .filter(ConverterMapperProcessor::isDelegatingConverterAnnotation)
            .map(roundEnv::getElementsAnnotatedWith)
            .flatMap(Set::stream)
            .map(ExecutableElement.class::cast)
            // Do not generate delegate without Mapper annotation on class
            .filter(annotatedMethod -> annotatedMethod.getEnclosingElement().getAnnotationMirrors().stream().anyMatch(x -> x.getAnnotationType().toString().equals(MAPPER)))
            .map(annotatedMethod -> new DelegatingConverterDescriptor(annotatedMethod, processingEnv))
            .collect(toList());

Custom converter:

public interface BaseMapper<S, T> extends Converter<S, T> {

    @Nullable
    T convert(@NonNull S source, @Context CycleAvoidingMappingContext context);

    @Nullable
    @Override
    @Named("baseConvert")
    default T convert(@NonNull S source) {
        return convert(source, new CycleAvoidingMappingContext());
    }

    // Annotation is not processed
    @DelegatingConverter
    @InheritInverseConfiguration
    default S invertConvert(T source) {
        return invertConvert(source, new CycleAvoidingMappingContext());
    }

    S invertConvert(T source, @Context CycleAvoidingMappingContext context);
}

Mapper:

@Mapper(config = MapperConfig.class)
public abstract class CarMapper implements BaseMapper<Car, CarDto> {

    // Required annotation to have delegate generated by processor
    @DelegatingConverter
    @Override
    public Car invertConvert(CarDto source) {
        return BaseMapper.super.invertConvert(source);
    }
}

Delegate:

@Component
public class  CarDtoToCarConverter implements Converter<CarDto, Car> {
  private  CarMapper delegateMapper;

  public CarDtoToCarConverter(@Autowired final CarMapper delegateMapper) {
    this.delegateMapper = delegateMapper;
  }

  @Override
  public Car convert(final CarDto source) {
    return delegateMapper.invertConvert(source);
  }
}

Wanted mapper:

@Mapper(config = MapperConfig.class)
public abstract class CarMapper implements BaseMapper<Car, CarDto> {
    // Nothing to override
}

Thanks

Bắt đầu trong ConverterMapperProcessor và theo dõi cách các phương thức @DelegatingConverter được thu thập từ roundEnv; so sánh quy trình đó với ví dụ BaseMapper được kế thừa. Hoàn tất khi annotation trên BaseMapper.invertConvert được nhận diện cho CarMapper mà không cần override và delegate tương ứng được sinh ra.