org.json4s.scalaz.JsonScalaz.scala Maven / Gradle / Ivy
/*
* Copyright 2009-2010 WorldWide Conferencing, LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.json4s
package scalaz
import _root_.scalaz._
import std.option._
trait Types {
type Result[+A] = ValidationNel[Error, A]
sealed abstract class Error extends Product with Serializable
case class UnexpectedJSONError(was: JValue, expected: Class[_ <: JValue]) extends Error
case class NoSuchFieldError(name: String, json: JValue) extends Error
case class UncategorizedError(key: String, desc: String, args: List[Any]) extends Error
case object Fail {
def apply[A](key: String, desc: String, args: List[Any]): Result[A] =
Validation.failureNel(UncategorizedError(key, desc, args))
def apply[A](key: String, desc: String): Result[A] =
Validation.failureNel(UncategorizedError(key, desc, Nil))
}
implicit val JValueMonoid: Monoid[JValue] = Monoid.instance(_ ++ _, JNothing)
implicit val JValueEqual: Equal[JValue] = Equal.equalA
trait JSONR[A] {
def read(json: JValue): Result[A]
}
trait JSONW[A] {
def write(value: A): JValue
}
trait JSON[A] extends JSONR[A] with JSONW[A]
implicit def Result2JSONR[A](f: JValue => Result[A]): JSONR[A] = new JSONR[A] {
def read(json: JValue) = f(json)
}
def fromJSON[A: JSONR](json: JValue): Result[A] = implicitly[JSONR[A]].read(json)
def toJSON[A: JSONW](value: A): JValue = implicitly[JSONW[A]].write(value)
def field[A: JSONR](name: String)(json: JValue): Result[A] = json match {
case JObject(fs) =>
fs.find(_._1 == name)
.map(f => implicitly[JSONR[A]].read(f._2))
.orElse(implicitly[JSONR[A]].read(JNothing).fold(_ => none, x => some(Success(x))))
.getOrElse(Validation.failureNel(NoSuchFieldError(name, json)))
case x =>
Validation.failureNel(UnexpectedJSONError(x, classOf[JObject]))
}
type EitherNel[+a] = NonEmptyList[Error] \/ a
def validate[A: JSONR](name: String) = Kleisli(field[A](name)).mapK[EitherNel, A](_.disjunction)
implicit def function2EitherNel[A](f: A => Result[A]): (A => EitherNel[A]) = (a: A) => f(a).disjunction
implicit def kleisli2Result[A](v: Kleisli[EitherNel, JValue, A]): JValue => Result[A] = v.run.andThen(_.validation)
def makeObj(fields: Iterable[(String, JValue)]): JObject =
JObject(fields.toList.map { case (n, v) => JField(n, v) })
}
object JsonScalaz extends Types with Lifting with Base with org.json4s.scalaz.Tuples