Value-class-derivations (vacade) is to reduce boilerplate needed to work with value classes and
different libraries.
It supports Scala 2.12 & 2.13.
Due to breaking changes and compatibility problems, vacade - for the time being - has two release paths (starting with 0.3.0):
Versions following regular semver conventions keeping all dependencies as updated as possible
Versions ending in -1 which pin akka-http at version 10.1.x (due to ecosystem compatibility issues)
Pick one or more target library (depending on release path):
libraryDependencies ++= Seq(
"com.github.cerst" %% "vacade-akka-http" % vacadeVersion,
"com.github.cerst" %% "vacade-avro4s" % vacadeVersion,
"com.github.cerst" %% "vacade-jsoniter-scala" % vacadeVersion
)Pick imports and derivations as needed:
import com.github.cerst.vacade.akka.http._
import com.githuc.cerst.vacade.avro4s._
import com.githuc.cerst.vacade.jsoniter_scala._
// dependent imports
import akka.http.scaladsl.server.PathMatcher1
import com.github.plokhotnyuk.jsoniter_scala.core.JsonCodec
import com.sksamuel.avro4s.{Decoder, Encoder, SchemaFor}
import io.estatico.newtype.macros.newtype
import io.estatico.newtype.ops._
object types {
@newtype
final class ItemId(val asInt: Int)
object ItemId {
// null.asInstanceOf is only required for AnyVal value classes due to https://github.com/scala/bug/issues/8097
// otherwise, you'll get a runtime NullPointerException when the resulting codec is first accessed
// leave it out for Newtype
implicit val jsonCodecForItemId: JsonCodec[ItemId] = vcJsonCodec.int(apply)(_.asInt, null.asInstanceOf[ItemId])
// due to a change in Avro4s 4.0, it is unfortunately no longer possible to have a single type implementing Encoder & Decoder
implicit val (
encoderForItemId: Encoder[ItemId],
decoderForItemId: Decoder[ItemId],
schemaForItemId: SchemaFor[ItemId]
) = vcAvro4s(apply)(_.value)
val pm: PathMatcher1[ItemId] = vcPathMatcher.int(apply)
def apply(value: Int): ItemId = {
value.coerce
}
}
}- Only add features & convenience which is missing from existing libraries
- i.e. don't provide methods for every single library/ feature out there
- Don't break with the design on a particular API
- i.e. don't retrofit implicits if the underlying library does not have them
- All libraries are configured as Provided
- All derivations methods are prefixed with
vcfollowed by the name of the target type (e.g.vcJsonCodec)- Whenever explicit specification of underlying types is required, the aforementioned methods become objects
having said types as method names (e.g.
vcJsonCodec.int).
These objects also document why they are necessary.
- Whenever explicit specification of underlying types is required, the aforementioned methods become objects
having said types as method names (e.g.
- Implementations should work as consistently as possible for
AnyValandnewtype.
