Hi guys, I'm having a problem with Room TypeConver...

# room

[nicopasso]

Hi guys, I'm having a problem with Room TypeConverters and Kotlin (I guess it's just a Room issue but since I'm using Kotlin for that, I consider it a Kotlin issue as well).
This is the class I'd like to persist or a shorter version of it:

@Entity
data class Customer(
    @PrimaryKey
    var id: Int,
    var name: String,
   var paymentAccounts: List<PaymentAccount>,
   var addresses: List<Address> )

What we want to acheive is a generic solution for TypeConverters.
This is the first not-a-100%-correct solution we came up with:

fun <T> fromList(list: T?): String? {
        list?.let {

            val gson = Gson()
            val type = object: TypeToken<T>(){}.type
            val json = gson.toJson(list, type)
            return json

        } ?: run {
            return null
        }
    }

    fun <T> toList(json: String?): T? {
        json?.let {
            
            val gson = Gson()
            val type = object: TypeToken<T>(){}.type
            val list = gson.fromJson<T>(json, type)
            return list

        } ?: run {
            return null
        }
    }

 @TypeConverter
    fun fromPaymentAccountList(list: List<PaymentAccount>?) = fromList(list)

    @TypeConverter
    fun toPaymentAccountList(json: String?) = toList<List<PaymentAccount>>(json)

 @TypeConverter
    fun fromAddressList(list: List<Address>?) = fromList(list)

    @TypeConverter
    fun toAddressList(json: String?) = toList<List<Address>>(json)

With this approach we have only one big problem: no compilation errors, no other errors BUT all the properties in the data class are converted to `LinkedTreeMap`s instead of POKOs.

Our Customer object fortunately is not so complicated but we have other classes with list of objects and each object contains another list of other objects. It makes no sense to me to write a converter for each type that I want to persist with Room. Is there a solution to this problem?