nullValuePropertyMappingStrategy not working

I have the following mapper

@Mapper(config = MappingConfig.class)
public interface PokerRoomMapper {

  @Mapping(target = "phase", nullValuePropertyMappingStrategy = NullValuePropertyMappingStrategy.IGNORE)
  PokerRoom pokerRoomDtoToPokerRoom(PokerRoomDto pokerRoomDto);

}

The pokerRoomDto which is passed to it has a “phase” field which can be null. I want this field to be ignored when it is null. But right now the “null” value still gets mapped to the pokerRoom entity.

If I just ignore the field in the mapper it works and the default value for phase in PokerRoom stays untouched however I dont want to always ignore it.

@Mapper(config = MappingConfig.class)
public interface PokerRoomMapper {

  @Mapping(target = "phase", ignore = true)
  PokerRoom pokerRoomDtoToPokerRoom(PokerRoomDto pokerRoomDto);

}

Answer

This works as designed. NullValuePropertyMappingStrategy is only applied to update method. It is not used for normal mappings.

I think that you are looking for NullValueCheckStrategy, if you use NullValueCheckStrategy#ALWAYS then MapStruct will always do a null check non the PokerRoomDto and only invoke the setter on the PokerRoom if the value was not null