PlaybackStoppedHandler.kt

class PlaybackStoppedHandler : RequestHandler {

    override fun canHandle(input: HandlerInput) =
        input.matches(Predicates.requestType(PlaybackStoppedRequest::class.java))

    override fun handle(input: HandlerInput): Optional<Response> {
        val request = input.requestEnvelope.request
        val intentRequest = request as PlaybackStoppedRequest

        val lastPlayedAudio = JacksonSerializer().deserialize(
            input.attributesManager.persistentAttributes["lastPlayedAudio"] as String,
            Audio::class.java
        )
        input.attributesManager.persistentAttributes["lastPlayedAudio"] =
            JacksonSerializer().serialize(
                lastPlayedAudio.copy(lastPlayedOffsetInMilliseconds = intentRequest.offsetInMilliseconds)
            )
        input.attributesManager.savePersistentAttributes()

        return input.responseBuilder.build()
    }
}