LiftModelValidation.scala

trait MaxLenValidation {
  val maxLen:Int
  msg :String
  override def validations = 
    valMaxLen( maxLen,msg )_ :: super.validations
}

class Memo extends LongKeyedMapper[Message] with IdPK {
  def getSingleton = Message
  
  object contents extends MappedString(this, 140) 
    with MaxLenValidation{
    val maxLen = 140
    val msg:String = "Too Long!"
  }
}