json: Make immutable implementations support Jackson ObjectMapper about immutables HOT 5 CLOSED

I'm thinking about it all morning.

1. Strawman approach

@Value.Immutable
abstract class Value {
   public abstract int a1();
   public abstract boolean a2();
   @JsonCreator
   public static Value of(@JsonProperty("a1") int a1, @JsonProperty("a2") boolean a2) {
      return ImmutableValue.builder().a1(a1).a2(a2).build();
   }
}

Manual approach is definitely insufficient and there will be a problems with many attributes, with optional attributes and so on.

1. Generate jackson serializers/deserializers

@Value.Immutable
@Json.JacksonSerializers
abstract class Value {
   public abstract int a1();
   public abstract boolean a2();
}

// then use generated serializers where the type is used or on abstract value type
@JsonSerialize(using=ValueJacksonSerializer.class)
@JsonDeserialize(using=ValueJacksonSerializer.class)
Value value;

1. Generating Jackson Modules. Problem with modules is that you need to register them and sometimes creation of ObjectMappers is out of direct control.

What do you think? I need some input, in particular, what is the main use case for ObjectMapper integration: serialize immutable object as part of other Jackson serialized object or to manually call ObjectMapper as shown in examples ?

from immutables.

I think the main use case would be the former: being able to use the beans with existing code which happens to use ObjectMapper.

I'm not sure I see the point of adding Jackson annotations to the abstract class: this would seem to defeat the purpose of this excellent library.

So actually I was thinking that you would make the immutable class the thing which supports ObjectMapper.

E.g.:

public final class ImmutableFoo
    extends Foo {
        @JsonCreator
        public static Value of(@JsonProperty("a1") int a1, @JsonProperty("a2") boolean a2) {
             return builder().a1(a1).a2(a2).build();
        }
    ...

from immutables.

Just released version 1.0 with Jackson integration.
Thank you for reporting this! Also, @cowtowncoder was able to fix bug in Jackson discovered during work on this request.
Please see @Jackson.Mapped annotation. I guess, this is a simplest possible way to integrate for now.
Documentation now is more or less updated for the changes in 1.0. Please see http://immutables.org

from immutables.

Fantastic! Thanks so much for this. I'm trying this out right now...:)

from immutables.

This works perfectly for me! Thanks so much - I think this will really help me persuade my colleagues to replace our bloated code with Immutable value types instead!

from immutables.