enumeratum decoder

enumeratum_circe.scala

import enumeratum._
import io.circe.Printer
import io.circe.parser._
import io.circe.syntax._
import org.scalatest.prop.TableDrivenPropertyChecks
import org.scalatest.{EitherValues, FlatSpec, Matchers}

import scala.collection.immutable.IndexedSeq

object foo {
// Caches for enum encoders and decoders.
  private val enumEncoderCache = new CompanionCache
  private val enumDecoderCache = new CompanionCache

  /**
    * Provides an encoder for any class that extends EnumEntry.
    *
    * Using java reflection it retrieves the EnumEntry's companion, and builds a circe encoder using the library
    * enumeratum-circe. The encoder is then cached using the type T.
    *
    * @tparam T The type of the enum, with a context bound also specifying that an `implicit ctag: ClassTag[T]` exists.
    *           https://www.scala-lang.org/files/archive/spec/2.12/07-implicits.html#context-bounds-and-view-bounds
    * @return The enum encoder.
    */
  implicit def encodeEnum[T <: EnumEntry: ClassTag]: Encoder[T] = {
    enumEncoderCache.cached[T, Enum[T], Encoder[T]](Circe.encoder)
  }

  /**
    * Provides a decoder for any class that extends EnumEntry.
    *
    * Using java reflection it retrieves the EnumEntry's companion, and builds a circe decoder using the library
    * enumeratum-circe. The decoder is then cached using the type T.
    *
    * @tparam T The type of the enum, with a context bound also specifying that an `implicit ctag: ClassTag[T]` exists.
    *           https://www.scala-lang.org/files/archive/spec/2.12/07-implicits.html#context-bounds-and-view-bounds
    * @return The enum decoder.
    */
  implicit def decodeEnum[T <: EnumEntry: ClassTag]: Decoder[T] = {
    enumDecoderCache.cached[T, Enum[T], Decoder[T]](Circe.decoder)
  }