What @JsonTypeInfo.ID to choose for property = “type.id” for deserialization, JsonTypeInfo.Id.CUSTOM?

Question

So I have JSON that looks like this:

{
    \"ActivityDisplayModel\" : {
        \"name\" : \"lunch with friends\",
        \"startTime\" : \"12:00:00\",
                 


        

Answer 1

I know it's been 3 years since the original question, but dot-nested properties are still not supported and maybe this will help someone out. I ended up creating a class NestedTypeResolver so we can use the dot-syntax as expected. Simply add @JsonTypeResolver(NestedTypeResolver.class) to any class with nested discriminators and the poster's original attempt will work:

/** 
 * My ActivityDisplayModel Abstract Class
 */
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type.id")
  @JsonSubTypes({
  @JsonSubTypes.Type(value = MealDisplayModel.class, name = "MEAL"),
  @JsonSubTypes.Type(value = EntertainmentDisplayModel.class, name = "ENTERTAINMENT")
})
@JsonTypeResolver(NestedTypeResolver.class)
public abstract class ActivityDisplayModel {

NestedTypeResolver:

/**
 * Allows using nested "dot" dyntax for type discriminators. To use, annotate class with @JsonTypeResolver(NestedTypeResolver.class)
 */
public class NestedTypeResolver extends StdTypeResolverBuilder {
    @Override
    public TypeDeserializer buildTypeDeserializer(DeserializationConfig config, JavaType baseType,
            Collection subtypes) {
            //Copied this code from parent class, StdTypeResolverBuilder with same method name
            TypeIdResolver idRes = idResolver(config, baseType, subtypes, false, true);
            return new NestedTypeDeserializer(baseType, idRes, _typeProperty, _typeIdVisible,
                null, _includeAs);
    }
}

All the heavy work is done in here, NestedTypeDeserializer:

/**
 * Heavy work to support {@link NestedTypeResolver}
 */
public class NestedTypeDeserializer extends AsPropertyTypeDeserializer {

    private static final Logger LOGGER = LoggerFactory.getLogger(NestedTypeDeserializer.class);

    public NestedTypeDeserializer(JavaType bt,
            TypeIdResolver idRes, String typePropertyName, boolean typeIdVisible,
            JavaType defaultImpl) {
        super(bt, idRes, typePropertyName, typeIdVisible, defaultImpl);
    }

    public NestedTypeDeserializer(JavaType bt, TypeIdResolver idRes, String typePropertyName, boolean typeIdVisible,
            JavaType defaultImpl, JsonTypeInfo.As inclusion) {
        super(bt, idRes, typePropertyName, typeIdVisible, defaultImpl, inclusion);
    }

    public NestedTypeDeserializer(AsPropertyTypeDeserializer src, BeanProperty property) {
        super(src, property);
    }

    @Override
    public TypeDeserializer forProperty(BeanProperty prop) {
        return (prop == _property) ? this : new NestedTypeDeserializer(this, prop);
    }

    @Override
    public Object deserializeTypedFromObject(JsonParser p, DeserializationContext ctxt) throws IOException {
        JsonNode originalNode = p.readValueAsTree();
        JsonNode node = originalNode;
        //_typePropertyName is the dot separated value of "property" in @JsonTypeInfo
        LOGGER.debug("Searching for type discriminator [{}]...", _typePropertyName);
        for (String property : _typePropertyName.split("\\.")) { //traverse down any nested properties
            JsonNode nestedProp = node.get(property);
            if (nestedProp == null) {
                ctxt.reportWrongTokenException(p, JsonToken.FIELD_NAME,
                        "missing property '" + _typePropertyName + "' that is to contain type id  (for class "
                                + baseTypeName() + ")");
                return null;
            }
            node = nestedProp;
        }
        LOGGER.debug("Found [{}] with value [{}]", _typePropertyName, node.asText());
        JsonDeserializer