On Sat, Nov 11, 2017 at 3:40 AM, Dawid Weiss <[email protected]> wrote: >> Unfortunately reading/writing Object Id values, references, requires >> support by value (de)serializers > > Thanks Tatu. I sort of figured it out. I also tried to implement > serialization inside > my own handler based on the infrastructure provided by Jackson > (annotations and ObjectIdReader, etc.), > but there seemed to be always some piece missing -- browsing through the code > those pieces are typically passed around but are not easily provided via the > contexts > (serialization or deserialization).
This is quite possible in that access may have been added in a way that just supports usage via BeanDeserializer/BeanSerializer. > I also checked the tests, but I didn't find any obvious example there. > > I would gladly resort to implementing my own id-resolution inside the > serializer -- this seems the easiest way to go, actually, > but I'd appreciate some help on understanding the lifecycle of the > "per-serialization/deserialization" contexts inside the > serializer and deserializer so that I can implement in in a nice way. Ok. So, contexts in question are: - DeserializationContext for deserialization - SerializerProvider for serialization (latter really should be `SerializationContext`, but that's since serialization side was fully develop (for something like 0.9.5 :-) ) before tackling deserialization -- this just for historical interest) and they are constructed during initialization of `readValue()` / `writeValue()` calls by `ObjectMapper` (and `ObjectReader` / `ObjectWriter`). Both contain attribute context, which you could use for keeping track of ids; you do not have to clean them up or anything as any values set are just dropped once `readValue()`/`writeValue()` call finishes. > I'll need a per-serialization (or deserialization) bidirectional > mapping between object IDs and objects. I can hack this > inside the serialize/deserialize methods and lazily check/ create a > custom attribute in SerializerProvider and > in DeserializationContext. Is there any nicer way of doing this you > can thing of? That sounds like a reasonable approach to me. If you did want to see how `ObjectIdReader` etc worked, you could check `BeanDeserializerBase` (from its construction from `BeanDeserializerBuilder` to `createContextual`). Actually one more thing that might be useful: if you could file an issue for `jackson-databind` for something like "Please include a test for Object Id handling for a custom type", that'd be useful. While I can't guarantee I'll do that, it's possible I might -- and I do go through issues as sort of todo list every now and then. I do think it should be doable and documented, even if only via unit tests: it is something that should be available for, say, datatype libraries. -+ Tatu +- > > Dawid > > -- > You received this message because you are subscribed to the Google Groups > "jackson-user" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "jackson-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. For more options, visit https://groups.google.com/d/optout.
