implementation case class instead of enumeration in lift Mongodb Record : SingleStringTypedField

SingleStringTypedField.scala

/*
* Copyright 2012 Heirko
*
* 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 code.field


import net.liftweb._
import record._
import field._

import reflect.Manifest
import xml._

import common._
import Box.option2Box
import json._
import util._
import Helpers._
import http.js._
import http.{S, SHtml}
import S._
import JE._



trait CaseEnum {
  def id : String
}


abstract class SingleStringTypedField[OwnerType <: Record[OwnerType], SingleStringType <: CaseEnum](rec: OwnerType) ( implicit mf: Manifest[SingleStringType])
  extends Field[SingleStringType, OwnerType] with MandatoryTypedField[SingleStringType] with BaseSingleStringTypedField[SingleStringType] {

  def owner = rec

  def setFromAny(in: Any): Box[SingleStringType] = in match {
    case seq: Seq[_] if !seq.isEmpty => setFromAny(seq.head)
    case _ => genericSetFromAny(in)
  }
}

trait BaseSingleStringTypedField[SingleStringType <: CaseEnum] extends TypedField[SingleStringType] {

  def fromString(s : String) : SingleStringType

  def setFromString(s: String): Box[SingleStringType] = s match {
    case "" if optional_? => setBox(Empty)
    case _                => setBox(Full(fromString(s)))
  }

  def toForm: Box[NodeSeq] = Empty

  def defaultValue = null.asInstanceOf[MyType]
  override def optional_? = true

  def asJs = valueBox.map(v => Str(v.id)) openOr JsNull

  def asJValue: JValue = valueBox.map(v => JString(v.id)) openOr (JNothing: JValue)
  def setFromJValue(jvalue: JValue): Box[MyType] = jvalue match {
    case JNothing|JNull if optional_? => setBox(Empty)
    case JString(s)                   => setFromString(s)
    case other                        => setBox(FieldHelpers.expectedA("JString", other))
  }
}