Determining deserialized POJO fields at runtime

[Volkan Yazıcı]

I have a bunch of POJOs deserialized from JSON strings. Is it possible to instruct Jackson at runtime to indicate which fields need to be deserialized? Consider the following POJO structure rooted at A:

class A {
    String a1;
    String a2;
    String a3;
    B b;
}

class B {
    String b1;
    String b2;
    C c;
}

class C {
    String c1;
    String c2;
}

At compile time I can generate 2^4 * 2^3 * 2^2 view classes to achieve what I want, but that sounds like an overkill. Is there simpler way to achieve this?

[Tatu Saloranta]

If this was about serialization, there are a few mechanism to do filtering dynamically, but for deserialization there's just JSON Views, and then streaming-level `FilteringParserDelegate` which could probably work but is some work to use.

Specific mechanism from serialization side that would be nice is JSON Filters (`@JsonFilter`), but unfortunately databind-side abstraction is serialization-specific (uses delegation, wherein filter calls write methods on things to pass).

I think what most developers do is to serialize/convert to an intermediate structure (JsonNode, Map), then filter out things they don't want, and then serialize that pruned version as JSON.

-+ Tatu +-