Hello everyone, I think I had a solution for the f...

# jackson-kotlin

[Philipp Mayer]

Hello everyone,
I think I had a solution for the following problem some time ago but I can’t think of one right now, so here I am:
I have the following structure:

sealed class ApiResult {
    data class Error(val errors: List<ApiError>) : ApiResult() {
        data class ApiError(
            val propertyName: String,
            val errorMessage: String,
            val errorCode: String,
        )
    }
}

And I want to serialize some response json into ApiResult.Error.
The Json looks like that:

[
  {
    "propertyName": "...",
    "errorMessage": "...",
    "errorCode": "..."
  }
]

So I have an object with holds a list of elements. Instantiating the object manually would look like that:

ApiResult.Error(objectMapper.readValue(""))

But I want to serialize directly into ApiResultError.

Usually I would do something along the lines of:

class ApiErrors: ArrayList<ApiErrors.ApiError>() {
        data class ApiError(
            val propertyName: String,
            val errorMessage: String,
            val errorCode: String,
        )

So, implementing the ArrayList. This does not work inside a sealed class.
Any idea? Thanks in advance!

[dinomite]

You might be able to make your error class look like this and get the behavior you want

Untitled

[dinomite]

That pair of annotations kind-of makes the Error object transparent

[Philipp Mayer]

Unfortunately, @JsonCreator is not applicable to target ‘class’

[dinomite]

Split out the constructor and apply it to that

[dinomite]

Untitled

Untitled

[Philipp Mayer]

Ah, I should’ve thought about that too. Thanks, works!

[dinomite]

It’s a weird syntax, not Kotlin’s best work (though necessary optimization for the more common use case)