MapStruct inheritance, more than one configuration prototype is application

Question

All my entities extends a base entity that has a Customer createdBy and String createdById field, and some more that work the same. I want to exclude the full Customer object when data is transferred around.

Some others entities extends another entity that itself extends the base entity, hence the following mappers :

@MapperConfig(componentModel = "spring", mappingInheritanceStrategy = MappingInheritanceStrategy.AUTO_INHERIT_FROM_CONFIG)
public interface AuditingEntityMapper<Dto, Entity> {

    @Mapping(target = "createdBy", source = "createdById")
    @Mapping(target = "lastModifiedBy", source = "lastModifiedById")
    Dto toDto(Entity entity);

    @Mapping(target = "createdBy", ignore = true)
    @Mapping(target = "lastModifiedBy", ignore = true)
    Entity toEntity(Dto dto);
}


@MapperConfig(componentModel = "spring", mappingInheritanceStrategy = MappingInheritanceStrategy.AUTO_INHERIT_FROM_CONFIG)
public interface ManageableEntityMapper<ManageableDtoType extends ManageableDTO, ManageableType extends Manageable> {

    ManageableDtoType toDto(ManageableType manageable);

    @Mapping(target = "project", ignore = true)
    ManageableType toEntity(ManageableDtoType dto);
}

Then I exploit those two mappers :

@Mapper(config = AuditingEntityMapper.class)
public interface ManageableStatusMapper {

    @Mapping(target = "project", ignore = true)
    @Mapping(target = "organization", ignore = true)
    ManageableStatus toEntity(ManageableStatusDTO manageableStatusDTO);

    default ManageableStatus fromId(String id) {
        if (id == null) {
            return null;
        }
        ManageableStatus manageableStatus = new ManageableStatus();
        manageableStatus.setId(id);
        return manageableStatus;
    }
}

// Returns this error and therefore others about mapping problems :
// More than one configuration prototype method is applicable. Use @InheritConfiguration to select one of them explicitly: java.lang.Object toDto(java.lang.Object entity), java.lang.Object toEntity(java.lang.Object dto).


@Mapper(config = ManageableEntityMapper.class)
public interface TaskMapper {

    @Mapping(target = "timeEntries", ignore = true)
    @Mapping(target = "assignments", ignore = true)
    Task toEntity(TaskDTO taskDTO);

    default Task fromId(String id) {
        if (id == null) {
            return null;
        }
        Task task = new Task();
        task.setId(id);
        return task;
    }
}
// Returns this error and one more of the same type :
// Can't map property "java.lang.String createdBy" to "com.acme.domain.Customer createdBy". Consider to declare/implement a mapping method: "com.acme.domain.Customer map(java.lang.String value)".

If my business mapper doesn't need extra mapping it works fine. Also, MapStruct seems to try to generate an implementation of both @MapperConfig annotated classes, which generates a lot of errors, but it's probably connected to all those classes connected to them.

How am I supposed to implement this behavior ? The doc about inheritance and/or shared configuration is very confusing to me.

Answer 1

This only works when ManageableStatus extends Entity and ManageableStatusDTO extends Dto.

The error message More than one configuration prototype method is applicable. Use @InheritConfiguration (where is it in on your example) means that you have to be explicit and possibly indicate the name of the method because more methods qualify.

so:

@Mapper(config = AuditingEntityMapper.class)
public interface ManageableStatusMapper {

    @InheritConfiguration // use this one to inherit stuf from the config
    @Mapping(target = "project", ignore = true)
    @Mapping(target = "organization", ignore = true)
    ManageableStatus toEntity(ManageableStatusDTO manageableStatusDTO);

    default ManageableStatus fromId(String id) {
        if (id == null) {
            return null;
        }
        ManageableStatus manageableStatus = new ManageableStatus();
        manageableStatus.setId(id);
        return manageableStatus;
    }
}

or.. if MapStruct has a conflict

@Mapper(config = AuditingEntityMapper.class)
public interface ManageableStatusMapper {

    @InheritConfiguration( name= "toDto" ) // really point to AuditingEntityMapper#toDto
    @Mapping(target = "project", ignore = true)
    @Mapping(target = "organization", ignore = true)
    ManageableStatus toEntity(ManageableStatusDTO manageableStatusDTO);

    default ManageableStatus fromId(String id) {
        if (id == null) {
            return null;
        }
        ManageableStatus manageableStatus = new ManageableStatus();
        manageableStatus.setId(id);
        return manageableStatus;
    }
}

or do it lazy

@Mapper(config = AuditingEntityMapper.class, mappingInheritanceStrategy = MappingInheritanceStrategy.AUTO_INHERIT_ALL_FROM_CONFIG )
public interface ManageableStatusMapper {

    // no explicit @InheritConfiguration required, because of AUTO_INHERIT_ALL_FROM_CONFIG
    @Mapping(target = "project", ignore = true)
    @Mapping(target = "organization", ignore = true)
    ManageableStatus toEntity(ManageableStatusDTO manageableStatusDTO);

    default ManageableStatus fromId(String id) {
        if (id == null) {
            return null;
        }
        ManageableStatus manageableStatus = new ManageableStatus();
        manageableStatus.setId(id);
        return manageableStatus;
    }
}

By the way: there's also @InheritInverseConfigiration