Caso Scala tiene 22 campos pero tiene problemas con play-json en scala 2.11.5

playframework playframework-2.3

Question

Con Scala 2.11, podemos tener más de 22 campos en una clase de caso, ¿no?

case class SomeResponse(
                                     var compositeKey: String,
                                     var id1: String,
                                     var id2: String,
                                     var firstName: String,
                                     var lastName: String,
                                     var email: String,
                                     var email2: String,
                                     var birth: Long,
                                     var gender: String,
                                     var phone: Phone,
                                     var city: String,
                                     var zip: String,
                                     var carriage: Boolean,
                                     var carriage2: Boolean,
                                     var fooLong: Long,
                                     var fooLong2: Long,
                                     var suspended: Boolean,
                                     var foo: Foo,
                                     var address: String,
                                     var suite: String,
                                     var state: String,
                                     var instructions: String)

implicit val formatSomeResponse = Json.format[SomeResponse]

Bueno, lo anterior es una clase de caso que tiene exactamente 22 campos con el formato play-json, ahora cuando compilo, recibo este error:

SomeFile.scala:126: value apply is not a member of play.api.libs.functional.FunctionalBuilder[play.api.libs.json.OFormat]#CanBuild22[String,String,String,String,String,String,String,Long,String,com.Phone,String,String,Boolean,Boolean,Long,Long,Boolean,com.Foo,String,String,String,String]

Y la clase de casos Phone y Foo, cada uno tiene dos campos cada uno.

Entonces, ¿por qué me enfrento al problema? No cruza el límite de 22 campos o hay algo más que hice mal, y lo intenté en la Scala 2.11.5 / 2.11.1 - play-json 2.3

Actualización: Basado en las respuestas de James y Phadej

  val someResponseFirstFormat: OFormat[(String, String, String, String, String, String, String, Long, String, Phone, String)] =
    ((__ / "compositeKey").format[String] and
      (__ / "id1").format[String] and
      (__ / "id2").format[String] and
      (__ / "firstName").format[String] and
      (__ / "lastName").format[String] and
      (__ / "email").format[String] and
      (__ / "email2").format[String] and
      (__ / "birth").format[Long] and
      (__ / "gender").format[String] and
      (__ / "phone").format[Phone] and
      (__ / "city").format[String]).tupled

  val someResponseSecondFormat: OFormat[(String, Boolean, Boolean, Long, Long, Boolean, Foo, String, String, String, String)] =
    ((__ / "zip").format[String] and
      (__ / "carriage").format[Boolean] and
      (__ / "carriage2").format[Boolean] and
      (__ / "fooLong").format[Long] and
      (__ / "fooLong2").format[Long] and
      (__ / "suspended").format[Boolean] and
      (__ / "foo").format[Foo] and
      (__ / "address").format[String] and
      (__ / "suite").format[String] and
      (__ / "country").format[String] and
      (__ / "instructions").format[String]).tupled

  implicit val formatSome: Format[SomeResponse] = (
    someResponseFirstFormat and someResponseSecondFormat
    ).apply({
    case ((compositeKey, id1, id2, firstName, lastName, email, email2, birth, gender, phone, city),
    (zip, carriage, carriage2, created, updated, suspended, foo, address, suite, country, instructions)) =>
      SomeResponse(compositeKey, id1, id2, firstName, lastName, email, email2, birth, gender, phone, city, zip, carriage, carriage2, created, updated, suspended, location, address, suite, country, instructions)
  }, huge => ((huge.compositeKey, huge.id1, huge.id2, huge.firstName, huge.lastName, huge.email, huge.email2, huge.birth, huge.gender, huge.phone, huge.city),
    (huge.zip, huge.carriage, huge.carriage2, huge.created, huge.updated, huge.suspended, huge.foo, huge.address, huge.suite, huge.country, huge.instructions)))

Answer 1

Para hacer el ejemplo anterior compilar, tuve que hacer el tipo explícito:

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

// Let''s pretend this is huge:
case class Huge(a: Int, b: String, c: Boolean, d: List[Int])

object Huge {
  val fields1to2: Reads[(Int, String)] = (
    (__ / "a").read[Int] and
    (__ / "b").read[String]
  ).tupled

  val fields3to4: Reads[(Boolean, List[Int])] = (
    (__ / "c").read[Boolean] and
    (__ / "d").read[List[Int]]
  ).tupled

  val f: ((Int, String), (Boolean, List[Int])) => Huge = {
    case ((a, b), (c, d)) => Huge(a, b, c, d)
  }

  implicit val hugeCaseClassReads: Reads[Huge] = (
    fields1to2 and fields3to4
  ) { f }

}

Answer 2

Puedes dividir la definición de tus Reads :

val fields1to10: Reads[(A,B,C,D,E,F,G,H,I,J)] = ???
val fields11to20 = ???
val fields21to30 = ???

implicit val hugeCaseClassReads: Reads[HugeCaseClass] = (
  fields1to10 and fields11to20 and fields21to30
) { a, b, c => createHugeCaseClassFromThreeTuples(a, b, c) }

La razón por la que la "sintaxis funcional" no funciona para más de 22 campos es porque hay clases intermedias definidas solo hasta 22: FunctionalBuilder

Completamente escrito para un pequeño ejemplo, se vería así:

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

// Let''s pretend this is huge:
case class Huge(a: Int, b: String, c: Boolean, d: List[Int])

val fields1to2: Reads[(Int, String)] = (
  (__ / "a").read[Int] and
  (__ / "b").read[String]
).tupled

val fields3to4: Reads[(Boolean, List[Int])] = (
  (__ / "c").read[Boolean] and
  (__ / "d").read[List[Int]]
).tupled

implicit val hugeCaseClassReads: Reads[Huge] = (
  fields1to2 and fields3to4
) {
  case ((a, b), (c, d)) =>  
    Huge(a, b, c, d)
}

Y el resultado de tryint para validar null :

scala> JsNull.validate[Huge]
res6: play.api.libs.json.JsResult[Huge] = JsError(
  List(
    (/b,List(ValidationError(error.path.missing,WrappedArray()))),
    (/d,List(ValidationError(error.path.missing,WrappedArray()))),
    (/c,List(ValidationError(error.path.missing,WrappedArray()))),
    (/a,List(ValidationError(error.path.missing,WrappedArray())))))

Como se puede ver, todos los campos son probados.

O podría extender el juego con más clases de CanBuildNN : https://github.com/playframework/playframework/blob/2.3.6/framework/src/play-functional/src/main/scala/play/api/libs/functional/Products.scala

Sin embargo, le aconsejo que SomeResponse los campos en la clase SomeResponse , por ejemplo, relacionados con la dirección, etc. Y escriba las instancias de Reads y Writes mano, si la estructura JSON es plana y no se puede cambiar.