#Play2.1 #Json Read 2 fields exclusively (accepts only one present) essaimodif #scala #nullable

_LICENSE.txt

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2013 YOUR_NAME_HERE <YOUR_URL_HERE>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

CODE.scala

import play.api.libs.json._
import play.api.libs.functional.syntax._

val r = (
  (__ \ "field1").readNullable[String] and 
  (__ \ "field2").readNullable[Int]
).tupled.filter(ValidationError("unexpected result")){ 
  case( Some(x), None ) => true; 
  case ( None, Some(x) ) => true; 
  case _ => false 
}

scala> Json.obj("field1" -> "toto").validate(r)
res19: play.api.libs.json.JsResult[(Option[String], Option[Int])] = JsSuccess((Some(toto),None),)
 
scala> Json.obj("field2" -> 5).validate(r)
res20: play.api.libs.json.JsResult[(Option[String], Option[Int])] = JsSuccess((None,Some(5)),)
 
scala> Json.obj("field2" -> "toto").validate(r)
res21: play.api.libs.json.JsResult[(Option[String], Option[Int])] = JsError(List((/field2,List(ValidationError(validate.error.expected.jsnumber,WrappedArray())))))
 
scala> Json.obj("field1" -> "toto", "field2" -> 5).validate(r)
res22: play.api.libs.json.JsResult[(Option[String], Option[Int])] = JsError(List((,List(ValidationError(unexpected result,WrappedArray())))))

Thanks !