In Gson, we leave it the type adapters that you can write for the classes
from third-party library.
Works well.
On Mon, Nov 9, 2015 at 10:11 AM, Dmitry Kornilov <dmitry.kornilov_at_oracle.com
> wrote:
> Hi Experts,
>
> We are preparing a second draft of JSON-B spec. There are a few topics we
> still need to discuss. I'll create a thread for each topic in the next few
> weeks.
>
> Today lets start with third party objects.
>
> *Use case:*
>
> We have an extenal jar with classes we need to process. We cannot add any
> annotations to these classes. Default configuration doesn't process it the
> desired way.
>
> *Options are:*
>
> *1. Jackson like MixIn annotations*
>
> For each third party class we want to customize an internal
> class/interface has to be created. This internal class has @Jsonb
> annotations defined the way how it should be in a third party class.
>
> More details:
> http://wiki.fasterxml.com/JacksonMixInAnnotations
>
> It covers most of the use cases and simple enough. The disadvantage I see
> is that configuration cannot be changed at runtime because conversion logic
> is defined in mix-in classes.
>
>
>
> *2. MOXy like external metadata format*
>
> All customizations are defined in external json document. This document
> has predefined format. This document is processed during JsonbConfig
> creation. Something similar to this:
>
> JsonbConfig config = new JsonbConfig()
> .withMetadata(fileInputStream);
>
>
> More details:
> https://wiki.eclipse.org/EclipseLink/Examples/MOXy/EclipseLink-OXM.XML
>
> I see it more complicated than mix-ins approach. The advantage is that
> customizations can be created at runtime.
>
>
> *3. Provide customization API (runtime annotations)*
>
> Define an API that allows adding customizations at runtime.
>
> Something similar to this:
>
> JsonbCustomizer customizer = new JsonbCustomizer();
> customizer.addJsonbNullableOnClass("package.ClassName", true);
>
> customizer.addJsonbPropertyOnField("package.ClassName", "fieldName",
> "value");
> customizer.addJsonbPropertyOnMethod("package.ClassName", "methodName",
> "value");
>
> JsonbConfig config = new JsonbConfig()
> .withCustomizer(customizer);
>
> I see it simple enough. Configuration can be created at runtime.
> Implementations can use this API to process external metadata files (like
> the MOXy one above).
>
>
> *4. Leave it as it is (not really an option) *
>
> We already have adapters. The disadvantage is that it can be not flexible
> enough in cases where the same type has to be processed differently in one
> configuration. It also lacks runtime configuration.
>
>
> Lets discuss the options. Feel free to suggest more options.
>
> Thanks,
> Dmitry Kornilov
>