Boolean defaultValue MapStruct

Question

I'm trying to set a defaultValue for a boolean field using MapStruct, but the generated code simply ignores it.

My code:

public class CreateEventRequest {

    @NotNull
    @JsonProperty
    private Boolean isPrivate;

    @JsonProperty
    private Boolean friendCanInviteFriends;

    @JsonProperty
    private boolean showGuestList;

    public boolean isPrivate() {
      return isPrivate;
     }

     public String getDescription() {
       return description;
     }

      public boolean isFriendCanInviteFriends() {
        return friendCanInviteFriends;
     }

      public boolean isShowGuestList() {
        return showGuestList;
     }
}

My mapper:

@Mapper(componentModel = "spring")
public interface CreateEventRequestMapper {
    @Mapping(target = "showGuestList", source = "showGuestList", defaultExpression = "java(true)")
    @Mapping(target = "friendCanInviteFriends", source = "friendCanInviteFriends", defaultValue = "true")
    Event map(CreateEventRequest request);
}

The generated code:

public class CreateEventRequestMapperImpl implements CreateEventRequestMapper {

    @Override
    public Event map(CreateEventRequest request) {
        if ( request == null ) {
            return null;
        }

        Event event = new Event();

        event.setShowGuestList( request.isShowGuestList() );
        event.setFriendCanInviteFriends( request.isFriendCanInviteFriends() );
        event.setPrivate( request.isPrivate() );

        return event;
    }
}

As you can see, I've tried using primitive/non-primitive type but it simply ignores the defaultValue.

Am I missing something here?

Thanks!

Answer 1

The problem is that the return type of your getter methods in the source object is always primitive which can't be null, you need to return Boolean .

MapStruct doesn't support direct private field access which requires reflection.