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Scala Serialization Guide
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scala_guide

Fury supports all scala object serialization:

  • case class serialization supported
  • pojo/bean class serialization supported
  • object singleton serialization supported
  • collection serialization supported
  • other types such as tuple/either and basic types are all supported too.

Scala 2 and 3 are both supported.

Install

libraryDependencies += "org.apache.fury" % "fury-core" % "0.7.1"

Fury creation

When using fury for scala serialization, you should create fury at least with following options:

val fury = Fury.builder()
  .withScalaOptimizationEnabled(true)
  .requireClassRegistration(true)
  .withRefTracking(true)
  .build()

Depending on the object types you serialize, you may need to register some scala internal types:

fury.register(Class.forName("scala.collection.generic.DefaultSerializationProxy"))
fury.register(Class.forName("scala.Enumeration.Val"))

If you want to avoid such registration, you can disable class registration by FuryBuilder#requireClassRegistration(false). Note that this option allow to deserialize objects unknown types, more flexible but may be insecure if the classes contains malicious code.

And circular references are common in scala, Reference tracking should be enabled by FuryBuilder#withRefTracking(true). If you don't enable reference tracking, StackOverflowError may happen for some scala versions when serializing scala Enumeration.

Note that fury instance should be shared between multiple serialization, the creation of fury instance is not cheap.

If you use shared fury instance across multiple threads, you should create ThreadSafeFury instead by FuryBuilder#buildThreadSafeFury() instead.

Serialize case object

case class Person(github: String, age: Int, id: Long)
val p = Person("https://github.com/chaokunyang", 18, 1)
println(fury.deserialize(fury.serialize(p)))
println(fury.deserializeJavaObject(fury.serializeJavaObject(p)))

Serialize pojo

class Foo(f1: Int, f2: String) {
  override def toString: String = s"Foo($f1, $f2)"
}
println(fury.deserialize(fury.serialize(Foo(1, "chaokunyang"))))

Serialize object singleton

object singleton {
}
val o1 = fury.deserialize(fury.serialize(singleton))
val o2 = fury.deserialize(fury.serialize(singleton))
println(o1 == o2)

Serialize collection

val seq = Seq(1,2)
val list = List("a", "b")
val map = Map("a" -> 1, "b" -> 2)
println(fury.deserialize(fury.serialize(seq)))
println(fury.deserialize(fury.serialize(list)))
println(fury.deserialize(fury.serialize(map)))

Serialize Tuple

val tuple = Tuple2(100, 10000L)
println(fury.deserialize(fury.serialize(tuple)))
val tuple = Tuple4(100, 10000L, 10000L, "str")
println(fury.deserialize(fury.serialize(tuple)))

Serialize Enum

Scala3 Enum

enum Color { case Red, Green, Blue }
println(fury.deserialize(fury.serialize(Color.Green)))

Scala2 Enum

object ColorEnum extends Enumeration {
  type ColorEnum = Value
  val Red, Green, Blue = Value
}
println(fury.deserialize(fury.serialize(ColorEnum.Green)))

Serialize Option

val opt: Option[Long] = Some(100)
println(fury.deserialize(fury.serialize(opt)))
val opt1: Option[Long] = None
println(fury.deserialize(fury.serialize(opt1)))

Performance

Scala pojo/bean/case/object are supported by fury jit well, the performance is as good as fury java.

Scala collections and generics doesn't follow java collection framework, and is not fully integrated with Fury JIT in current release version. The performance won't be as good as fury collections serialization for java.

The execution for scala collections will invoke Java serialization API writeObject/readObject/writeReplace/readResolve/readObjectNoData/Externalizable with fury ObjectStream implementation. Although org.apache.fury.serializer.ObjectStreamSerializer is much faster than JDK ObjectOutputStream/ObjectInputStream, but it still doesn't know how use scala collection generics.

In future we plan to provide more optimization for scala types, see apache#682, stay tuned!

Scala collections serialization is finished in apache#1073, if you want better performance, please use fury snapshot version.