custom deserialization with json4s for date in string format to timestamp (long)

custom_deser.scala

import org.joda.time.DateTime
import org.joda.time.format.DateTimeFormat
import org.json4s._
import org.json4s.native.JsonMethods._


val datePattern = "yyyy-MM-dd hh:mm:ss.SSSSSS"
val s = """{"timestamp": "2016-09-29 11:31:13.247772", "domain": "d1", "filePath": "s3://..."}"""
case class Event(domain : String, filePath : String, timestamp : Long)

object StringToLong extends CustomSerializer[Long](format => (
  { case JString(x) =>  DateTime.parse(x, DateTimeFormat.forPattern(datePattern)).getMillis}, 
  { case x: Long => JInt(x) }))

implicit val formats = DefaultFormats + StringToLong

val event = parse(s).extract[Event]