用circe实现对StackOverflowError的编码

Question

我正在为我的case类编写测试，在下面的测试中我有一个StackOverflowError：

  test("ValuationRequest - Conversion between case object and Json works") {
    val caseObject = ValuationRequest(TIME_SERIES_INTRADAY, "", IntraDayIntervals.MIN_5)
    val jsonString = caseObject
      .asJson
      .printWith(Printer.noSpaces)

    decode[ValuationRequest](jsonString) must be(Right(caseObject))
  }

下面是堆栈跟踪：

An exception or error caused a run to abort. 
java.lang.StackOverflowError
    at io.circe.syntax.package$EncoderOps$.asJson$extension(package.scala:10)
    at eventbus.ValuationRequest$.$anonfun$encodeRequest$1(ValuationRequestCases.scala:14)
....

这是案例代码：

import AV_Enums.TimeSeriesFunctions.TIME_SERIES_INTRADAY
import AV_Enums.{IntraDayInterval, IntraDayIntervals, TimeSeriesType}
import cats.syntax.functor._
import io.circe.generic.auto._
import io.circe.generic.semiauto._
import io.circe.syntax._
import io.circe.{Decoder, Encoder}

case class ValuationRequest(function: TimeSeriesType = TIME_SERIES_INTRADAY, symbol: String, interval: IntraDayInterval = IntraDayIntervals.MIN_5)

object ValuationRequest {
  implicit val encodeRequest: Encoder[ValuationRequest] = Encoder.instance { case response@ValuationRequest(_, _, _) => response.asJson }
  implicit val decodeRequest: Decoder[ValuationRequest] = deriveDecoder[ValuationRequest].widen
}

下面是它使用的枚举：

sealed abstract class TimeSeriesType(val text: String) extends EnumEntry {}

sealed abstract class IntraDayInterval(val text: String) extends EnumEntry {}

object TimeSeriesFunctions extends Enum[TimeSeriesType] with CirceEnum[TimeSeriesType] {
  val values: immutable.IndexedSeq[TimeSeriesType] = findValues

  case object TIME_SERIES_INTRADAY extends TimeSeriesType("TIME_SERIES_INTRADAY")

  case object TIME_SERIES_DAILY extends TimeSeriesType("TIME_SERIES_DAILY")

  case object TIME_SERIES_WEEKLY extends TimeSeriesType("TIME_SERIES_WEEKLY")

  case object TIME_SERIES_MONTHLY extends TimeSeriesType("TIME_SERIES_MONTHLY")

}

object IntraDayIntervals extends Enum[IntraDayInterval] with CirceEnum[IntraDayInterval] {
  val values: immutable.IndexedSeq[IntraDayInterval] = findValues

  case object MIN_1 extends IntraDayInterval("1min")

  case object MIN_5 extends IntraDayInterval("5min")

  case object MIN_15 extends IntraDayInterval("15min")

  case object MIN_30 extends IntraDayInterval("30min")

  case object MIN_60 extends IntraDayInterval("60min")

}

我不明白这个例子是怎么回事，其他的都工作得很好，而且都是以同样的方式实现的。有人能帮上忙吗？

Answer 1

有问题的线

Encoder.instance { case response@ValuationRequest(_, _, _) => response.asJson }

这里的.asJson需要Encoder[ValuationRequest]，这是一个递归调用。您不能使用deriveEncoder[ValuationRequest]的任何原因