gnieh.diffson.JsonProvider.scala Maven / Gradle / Ivy

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/*
* This file is part of the diffson project.
* Copyright (c) 2016 Lucas Satabin
*
* 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 gnieh.diffson

import scala.language.higherKinds

trait JsonSupport[JsValue] {
  this: DiffsonInstance[JsValue] =>

  /** The Json provider acts as an abstraction layer over the Json library.
   *  It exposes all methods and types used by diffson when manipulating Json values directly.
   *
   *  @author Lucas Satabin
   */
  abstract class JsonProvider {

    type Marshalling[T]

    type PointerErrorHandler = PartialFunction[(JsValue, String, Pointer), JsValue]

    implicit def defaultHandler: PointerErrorHandler = {
      case (_, name, parent) =>
        throw new PointerException(s"element $name does not exist at path $parent")
    }

    implicit val pointer = new JsonPointer()

    implicit val patchMarshaller: Marshalling[JsonPatch]

    def parseJson(s: String): JsValue

    def unapplyArray(value: JsValue): Option[Vector[JsValue]]

    def applyArray(elems: Vector[JsValue]): JsValue

    def unapplyObject(value: JsValue): Option[Map[String, JsValue]]

    def applyObject(fields: Map[String, JsValue]): JsValue

    val JsNull: JsValue

    def marshall[T: Marshalling](value: T): JsValue

    def unmarshall[T: Marshalling](value: JsValue): T

    def prettyPrint(value: JsValue): String

    def compactPrint(value: JsValue): String

    object JsArray {

      @inline
      def apply(elems: Vector[JsValue]): JsValue =
        applyArray(elems)

      @inline
      def unapply(value: JsValue): Option[Vector[JsValue]] =
        unapplyArray(value)

    }

    object JsObject {

      @inline
      def apply(fields: Map[String, JsValue]): JsValue =
        applyObject(fields)

      @inline
      def unapply(value: JsValue): Option[Map[String, JsValue]] =
        unapplyObject(value)

    }

  }
}