Add multiple mixins to one class with Jackson

Question

I have to minins:

@JsonIdentityInfo(generator=ObjectIdGenerators.None.class,
                  property="@id")
public interface NoReferenceMixin {

}
@JsonTypeInfo(use=JsonTypeInfo.Id.CLASS,
              include=JsonTypeInfo.As.PROPERTY,
              property="@class")
public interface FullClassInfoMixin { }

I want to apply both of these to a particular class, Thing. It appears that I can only add one Mixin per class, as evidenced by experiment and the existing of ObjectMapper.findMixInForClass which returns a single Class.

I have tried making an interface that extends both:

public interface ThingMixins extends NoReferenceMixin, FullClassInfoMixin { }

findMixInForClass returns the mixing, but FullClassInfoMixin is not applied. (It is harder to check if NoReferenceMixin is applied and I have not checked that.)

What is the correct way to do this?

I am using jackson 2.9.0.pr4

score 0 · Answer 1 · answered Feb 07 '18 at 01:16

Your work-around of having an interface that extends 2 interfaces you want to combine should work; annotations are scanned from specific mixin class throughout inheritance chain.

If you can reproduce the problem with simple example maybe file an issue against jackson-databind.

Add multiple mixins to one class with Jackson

1 Answers1