Defaults mode

Here's a basic usage using Defaults mode.

scala> import scala.pickling.Defaults._, scala.pickling.json._
scala> case class Person(name: String, age: Int)

scala> val pkl = Person("foo", 20).pickle
pkl: pickling.json.pickleFormat.PickleType =
JSONPickle({
  "$type": "Person",
  "name": "foo",
  "age": 20
})

scala> val person = pkl.unpickle[Person]
person: Person = Person(foo,20)

The Defaults mode automatically derives Pickler[Person] from the primitive picklers at compile-time! Because the code is statically generated, we can inline the string manipulations and make it fast. (Faster than Java serialization or Kryo, which also does not require schema)

Note, because Pickler[A] is a typeclass, Pickling can be retrofitted to Person without modifying the class to inherit Serializable or something like that.

DIY protocol stack

Pickling 0.10.0 offers picklers, ops, and formats as traits, which can be stacked together, so third-party libraries can provide custom modes. Suppose you only want to pickle primitive types and Apple, and don't want to automatically derive pickler combinators. Here's a custom mode:

scala> case class Apple(kind: String)
scala> val appleProtocol = {
         import scala.pickling._
         new pickler.PrimitivePicklers with pickler.RefPicklers
             with json.JsonFormats {
           // Manually generate pickler for Apple
           implicit val applePickler = PicklerUnpickler.generate[Apple]
           // Don't fall back to runtime picklers
           implicit val so = static.StaticOnly
           // Provide custom functions
           def toJsonString[A: Pickler](a: A): String =
             functions.pickle(a).value
           def fromJsonString[A: Unpickler](s: String): A =
             functions.unpickle[A](json.JSONPickle(s))
         }
       }
scala> import appleProtocol._

scala> toJsonString(Apple("honeycrisp"))
res0: String =
{
  "$type": "Apple",
  "kind": "honeycrisp"
}

For more details see Pickling.