com.pubnub.internal.utils.PolymorphicDeserializer.kt Maven / Gradle / Ivy

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package com.pubnub.internal.utils

import com.google.gson.JsonDeserializationContext
import com.google.gson.JsonDeserializer
import com.google.gson.JsonElement
import java.lang.reflect.Type

internal class PolymorphicDeserializer(
    private val defaultClass: Class? = null,
    private val findTargetClass: (JsonElement, Type) -> Class?,
) : JsonDeserializer {
    companion object {
        inline fun  dispatchByFieldsValues(
            fields: List,
            mappingFieldValuesToClass: Map, Class>,
            defaultClass: Class? = null,
        ): JsonDeserializer {
            val mappingWithList: Map, Class> = mappingFieldValuesToClass.mapKeys { it.key.toList() }
            return PolymorphicDeserializer(defaultClass = defaultClass) { jsonElement, _ ->
                val jsonObject = jsonElement.asJsonObject
                val fieldsValues: List = fields.map { jsonObject[it].asString }.toList()

                mappingWithList[fieldsValues]
            }
        }
    }

    override fun deserialize(
        json: JsonElement,
        typeOfT: Type,
        context: JsonDeserializationContext,
    ): T {
        val targetClass =
            findTargetClass(json, typeOfT) ?: defaultClass
                ?: error("When deserializing to $typeOfT no target class have been found and default class was not provided")
        return context.deserialize(json, targetClass)
    }
}