This is my class parsing special fuckeup JSONs where instead `"key":numericValue` I get `"key":"numericValue"`. I use https://github.com/spray/spray-json

MyJsonProtocol.scala

import spray.json._

object MyJsonProtocol extends DefaultJsonProtocol {

  implicit object MetricJsonFormatDouble extends RootJsonFormat[Metric[Double]] {
    def write(c: Metric[Double]) = JsObject()

    def read(value: JsValue) = value.asJsObject.getFields("total", "ok", "ko") match {
      case Seq(JsString(total), JsString(ok), JsString(ko)) =>
        Metric[Double](total.toDouble, ok.toDouble, ko.replace("-", "0").toDouble)
      case _ => deserializationError("Metric expected")
    }
  }

  implicit object MetricJsonFormatInt extends RootJsonFormat[Metric[Int]] {
    def write(c: Metric[Int]) = JsObject()

    def read(value: JsValue) = value.asJsObject.getFields("total", "ok", "ko") match {
      case Seq(JsString(total), JsString(ok), JsString(ko)) =>
        Metric[Int](total.toInt, ok.toInt, ko.replace("-", "0").toInt)
      case _ => deserializationError("Metric expected")
    }
  }

}