GitHub - evolution-gaming/kryo-macros: Scala macros for compile-time generation of Kryo serializers (original) (raw)

Scala macros that generate com.esotericsoftware.kryo.Serializer implementations in compile time, based on compile time reflection.

Features and limitations

• On top level only case classes are supported
• Fields of case classes can be other case classes, Scala collections, options, primitive or AnyVal types & classes, tuples, Scala enums, standard types & classes: String, Either, BigDecimal, java.time.Instant,scala.concurrent.duration.FiniteDuration, org.joda.time.DateTime
• Fields can be annotated as transient or just be not defined in constructor to avoid parsing and serializing
• For nested structures need to generate serializers for all case classes
• Implicitly defined mapping helpers are supported for ADT structures, simple alternative mappings, etc.
• Manual serializers can be used in generated code when defined as implicits

How to use

Add the following resolver

resolvers += Resolver.bintrayRepo("evolutiongaming", "maven")

Add the library to your dependencies list

libraryDependencies += "com.evolutiongaming" %% "kryo-macros" % "1.3.0"

Generate some serializers for your case classes

import com.evolutiongaming.kryo.Serializer

case class Player(name: String)

val serializer = Serializer.make[Player]

That's it! You have generated a com.esotericsoftware.kryo.Serializer implementation for your Player. You must know what to do with it if you are here :)

To serialize objects that extends sealed traits/class use Serializer.makeCommon call:

import com.evolutiongaming.kryo.{ConstSerializer, Serializer}

sealed trait Reason

object Reason { case object Close extends Reason case object Pause extends Reason
}

val reasonSerializer = Serializer.makeCommon[Reason] { case 0 => ConstSerializer(Reason.Close) case 1 => ConstSerializer(Reason.Pause) }

sealed abstract class Message(val text: String)

object Message { case object Common extends Message("common") case object Notification extends Message("notification") }

private implicit val messageSerializer = Serializer.makeMapping[Message] { case 0 => Message.Common
case 1 => Message.Notification }

To see generated code just add the following line to your sbt build file

scalacOptions += "-Xmacro-settings:print-serializers"

For more examples, please, check outSerializerMacroSpec

How to develop

Run tests, check coverage & binary compatibility for both supported Scala versions

sbt clean +coverage +test +coverageReport +mimaReportBinaryIssues

Run benchmarks

sbt -no-colors clean 'benchmark/jmh:run -prof gc .SerializerBenchmark.' >results.txt

Release

For version numbering use Recommended Versioning Schemethat is widely adopted in the Scala ecosystem.

Double-check binary & source compatibility and release using following command (credentials required):