Example of automatic case class extraction from JSON using Rapture JSON 0.9.2

extraction.scala

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scala> import rapture.core._
import rapture.core._

scala> import rapture.json._
import rapture.json._

scala> import jsonParsers.scalaJson._ // in Rapture JSON 0.10, import jsonBackends.scalaJson._
import jsonParsers.scalaJson._

scala> import strategy.throwExceptions // not required in Rapture JSON 0.10
import strategy.throwExceptions

scala> val molecule = json"""
     | {
     |   "name": "Sodium bicarbonate",
     |   "elements": [
     |     { "name": "Hydrogen", "count": 1, "unitMass": 1.00794 },
     |     { "name": "Carbon", "count": 1, "unitMass": 12.0107 },
     |     { "name": "Oxygen", "count": 3, "unitMass": 15.9994 },
     |     { "name": "Sodium", "count": 1, "unitMass": 22.989769 }
     |   ]
     | }
     | """
molecule: rapture.io.Json = 
{
 "name": "Sodium bicarbonate",
 "elements": [
  {
   "name": "Hydrogen",
   "count": 1.0,
   "unitMass": 1.00794
  },
  {
   "name": "Carbon",
   "count": 1.0,
   "unitMass": 12.0107
  },
  {
   "name": "Oxygen",
   "count": 3.0,
   "unitMass": 15.9994
  },
  {
   "name": "Sodium",
   "count": 1.0,
   "unitMass": 22.989769
  }
 ]
}

scala> case class Element(name: String, count: Int, unitMass: Double)
defined class Element

scala> molecule.elements(1).as[Element]
res0: Element = Element(Carbon,1,12.0107)

scala> case class Molecule(name: String, elements: List[Element]) { def mass = elements.map(c => c.count*c.unitMass).sum }
defined class Molecule

scala> molecule.as[Molecule]
res1: Molecule = Molecule(Sodium bicarbonate,List(Element(Hydrogen,1,1.00794), Element(Carbon,1,12.0107), Element(Oxygen,3,15.9994), Element(Sodium,1,22.989769)))

scala> res1.mass
res2: Double = 84.006609