Custom formatters for JodaTime DateTime and various case classes

ApiFormats.scala

package format

import model._
import spray.json._
import org.joda.time.DateTime
import org.joda.time.format.{ISODateTimeFormat, DateTimeFormatter}

/**
 * @version $Id$ $Rev: 223159 $ $Date: 2013-11-27 15:12:03 -0800 (Wed, 27 Nov 2013) $
 */
object ApiFormats extends DefaultJsonProtocol {

  implicit object DateTimeFormat extends RootJsonFormat[DateTime] {

    val formatter = ISODateTimeFormat.basicDateTimeNoMillis

    def write(obj: DateTime): JsValue = {
      JsString(formatter.print(obj))
    }

    def read(json: JsValue): DateTime = json match {
      case JsString(s) => try {
        formatter.parseDateTime(s)
      }
      catch {
        case t: Throwable => error(s)
      }
      case _ =>
        error(json.toString())
    }

    def error(v: Any): DateTime = {
      val example = formatter.print(0)
      deserializationError(f"'$v' is not a valid date value. Dates must be in compact ISO-8601 format, e.g. '$example'")
    }
  }

  implicit val bibFormat = jsonFormat15(Bib)
  implicit val materialTypeFormat = jsonFormat2(MaterialType)
  implicit val bibLevelFormat = jsonFormat2(BibLevel)
  implicit val fixedFieldFormat = jsonFormat4(FixedField)
  implicit val varFieldFormat = jsonFormat6(VarField)
  implicit val subFieldFormat = jsonFormat2(SubField)
}