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

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PubNub is a cross-platform client-to-client (1:1 and 1:many) push service in the cloud, capable of broadcasting real-time messages to millions of web and mobile clients simultaneously, in less than a quarter second!

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package com.pubnub.api.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)
    }
}