How to make work TypeResolverBuilder with registerSubtypes

Hello,

I can’t use annotations because it’s a external library so I neeed to register subTypes for an interface and set custom type handler.

I searched and tried multiple guides but without sucess

This is the code that I tried but without sucess, typeResolver is working but Jackson not matching the registered subTypes with the type.

TypeResolverBuilder<?> typeResolver = new ObjectMapper.DefaultTypeResolverBuilder(ObjectMapper.DefaultTyping.NON_FINAL, BasicPolymorphicTypeValidator.builder()
                .allowIfBaseType(BeOutMessage.class)
                .build());
        typeResolver.init(JsonTypeInfo.Id.NAME, null);
        typeResolver.inclusion(JsonTypeInfo.As.PROPERTY);
        typeResolver.typeProperty("action");

        mapper.registerSubtypes(
                new NamedType(InitRequestBeMessage.class, ActionType.INIT_REQUEST.name()),
                new NamedType(PlayRequestBeMessage.class, ActionType.PLAY_REQUEST.name())
        );
        mapper.setDefaultTyping(typeResolver);

I get this error:

typecom.fasterxml.jackson.databind.exc.InvalidTypeIdException: Could not resolve type id 'INIT_REQUEST' as a subtype of `classpath.BeOutMessage`: known type ids = []

The most easiest solution that I found is use JsonDeserializer:

public class BeOutMessageDeserializer extends JsonDeserializer<BeOutMessage> {

    @Override
    public BeOutMessage deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
        JsonNode jsonNode = p.getCodec().readTree(p);
        Class<? extends BeOutMessage> entityClass = BeOutMessageType.valueOf(jsonNode.get("action").asText()).entityClass();
        return ((ObjectMapper)p.getCodec()).readValue(jsonNode.toString(), entityClass);
    }
}
   

But I don’t like it and I don’t think that is efficient enough like the JsonSubTypes. How would be the proper way to do it at runtime?

Thank you!

[xdrsynapse]

After some performance tests agaisnt mixin I got this results:

mixin:
Total execution time: 438ms
Total execution time: 217ms
Total execution time: 122ms
Total execution time: 183ms

customDeserializer:
Total execution time: 748ms
Total execution time: 370ms
Total execution time: 269ms
Total execution time: 336ms

And it improves a little bit when using with mapper.readerFor. Ergo we will use mixin and I hope that other devs can get usefull this issue for info.

Thanks @yawkat, I think we can close the issue if there is nothing else to add

[cowtowncoder]

One note after the fact: if you use “Default Typing”, registration of subtypes has no effect – Default Typing specifically forces use of class names (and potentially opens up security holes). Subtype registration is (only) used when Type Ids are used instead – a safer approach, but one that does require mapping.

It sounds like mix-ins could work here, but use of TypeResolverBuilder would not make any sense to me.