Registering a converter for a type might incorrectly affect serializer construction

[odrotbohm]

Describe your Issue

Assume you have an interface / implementation arrangement for values to be serialized:

interface MyInterface {
  String getProperty();
}
class MyImplementation implements MyInterface {

  String getProperty() { … }
  String getAnotherProperty() { … }
}

If you register a StdConverter<MyInterface, MyInterface> to pre-process a value to be serialized, BeanSerializer.createSerializer(…) inspects the converter's target type, and builds a serializer for that explicitly. This causes getAnotherProperty() being lost for serialization as only MyInterface gets inspected, not MyImplementation.

I can see that you cannot simply use the original value's type as source for the serializer creation, as the converter could theoretically convert into any MyInterface implementation. So I wonder how I'd post-process an instance before serialization, but still make sure it gets serialized as this particular instance. I cannot change the declaration of the converter, as I do not control the implementing types.

Is there any other abstraction I could use to get a call for one or each time a certain type is serialized? In this particular case, I do not even need access to the value, as I'd like to log a message only.

References

• Document changes in rendering of PageImpl instances in Spring Boot 3.3 migration guide spring-projects/spring-boot#41856

[cowtowncoder]

If I understand the question, it's whether there is a hook you could register when attempting to serialize a value (instance) of a type. Short answer is "no".

But such feature (pre-serialization hook) has been requested before -- and I think there may be an issue for ... ah, this:

#2045

which is one of "Most Wanted" issues, too.

So contribution for adding would be welcome.