How to simply provide a target class in a custom deserializer?

[cwhite102]

Hi, I'm struggling to find how to implement this which probably is very easy...
I need to deserialize a polymorphic java class but need a little bit of code to choose which subclass should be instantiated.
What deserializer should I override, and once I determine the target class, how do I specify this class and continue with the default deserialization behavior?

I'd like to simply annotate the common parent class to use my deserializer.

The behaviour should be very similar to using @JsonTypeInfo and @JsonSubTypes specifying classes. The difference is that I need to have some custom code logic instead of just annotating which class to instantiate.

[cowtowncoder]

Polymorphic type detection is not done by actual JsonDeserializer but TypeDeserializer, configuration of which is by annotations (or "Default Typing"). There is no simple way to override this functionality.

[cwhite102]

Thanks for the quick response, I guess I'll need to do it up a level in the hierarchy where these objects were basically in a Map field.
This is how it was done currently using Gson, but I'm converting it to Jackson.
I thought the proposed approach would have been much cleaner than all the custom deserialization of the map itself.

[cowtowncoder]

Right: it'd be great to be able to customize aspects, but the way polymorphic handling is implemented was not designed for overridability.

There are some pieces that might allow customization (maybe check how @JsonTypeResolver and @JsonTypeIdResolver are handled) but nothing super straight-forward.