Hi everyone. I’m trying to create a custom Seriali...

# serialization

[Ivan Colovic]

Hi everyone.
I’m trying to create a custom Serializer for the following class.

class TreeNode(
    val value: MyData
) {
    val children = listOf<TreeNode>()
}

I’m trying to have the value field named dynamically based on its type (many classes inherit from MyData). Something like:

{
   "data_one":{
      ...
   },
   "children":[
      {
         "data_two":{
            ...
         },
         "children":[
            {
               "data_three":{
                  ...
               },
               "children":[
                  
               ]
            },
            {
               "data_one":{
                  ...
               },
               "children":[
                  
               ]
            }
         ]
      }
   ]
}

How do I define the SerialDescriptor element that represents the collection of its own type? Right now, I have:

override val descriptor: SerialDescriptor = buildClassSerialDescriptor("TreeNode") {
        element<DataOne>("data_one")
        element<DataTwo>("data_two")
        element<DataThree>("data_three")
        element("children", listSerialDescriptor<TreeNode>()) // this crashes because I'm trying to use the descriptor I'm currently creating
    }

When I change the listSerialDescriptor<TreeNode>() to for example listSerialDescriptor<String>() it encodes it the way I want it to, but I'm getting errors when decoding.
How do I approach this? Still new to the library I hope I was clear enough 🙇‍♂️ Thanks!

[Nikky]

when you use a sealed class it will have a type specifier and all work magically

and you can configure it to be using any key by setting classDiscriminator

[Nikky]

or you can use something like JsonTransformingSerializer to pick the right serializer basedo n the jsonElement you are getting

[Nikky]

i was bored.. so i made hacked something that matches that structure together:
https://gist.github.com/NikkyAI/f7a9d0deb64a346c0a691c16da250815

[Nikky]

but.. sealed classes default behaviour would be prettier still

[Ivan Colovic]

Wow! Thanks a lot. Much appreciated 🙇