Json.scala

import com.twitter.bijection._
import com.twitter.bijection.json.JsonInjection
import com.twitter.bijection.json.JsonNodeInjection._ // implicits required for building up JsonInjections from primitives

// Here's some custom case class that we'd like to be able to serialize into Json.
case class Wrapper(x: Int, y: Long)

// Now, we define a Bijection from our case class to a tuple.
val wrapperToTuple = Bijection.build[Wrapper, (Int, Long)](Wrapper.unapply(_).get)(Wrapper.tupled(_))

// Next we'll compose this with the library-supplied injection from Product -> String provided by JsonInjection:
val wrapperToString: Injection[Wrapper,String] = wrapperToTuple.andThen(JsonInjection.toString[(Int, Long)])

// Forward gets us to string, always:
val json: String = wrapperToString(Wrapper(10, 11L)) // String = [10,11]

// Invert returns a try:
wrapperToString.invert(Wrapper(10, 11L)) // scala.util.Try[Wrapper] = Success(Wrapper(10,11))