gistfile1.scala

class QuerySettings(pageSize: Option[Int] = Some(25), pageNumber: Option[Long] = Some(0), sortBy: Option[String] = None, direction: Option[String] = None, allParams: Map[String, String]) {
  sealed trait Direction
  sealed object Asc extends Direction
  sealed object Desc extends Direction
  sealed object Invalid extends Direction

  sealed trait Operator
  sealed object Equal extends Operator
  sealed object LessThan extends Operator
  sealed object LessThanOrEqual extends Operator
  sealed object GreaterThan extends Operator
  sealed object GreaterThanOrEqual extends Operator
  sealed object NotEqual extends Operator

  case class Filter(column: String, operator: Operator)


  val sortDirection = direction match {
    case None => Desc
    case Some("asc") => Asc
    case Some("desc") => Desc
    case _ => Invalid
  }

  require(sortDirection != Invalid, "Sort direction must be asc or desc.")

  require(allParams.size < 100, "Why are you trying to give me so many parameters?")

  val filters: Map[String, Filter] = allParams filter { x => 
    x._1 != "pageSize" && 
    x._1 != "pageNumber" && 
    x._1 != "sortBy" && 
    x._1 != "direction"} map { x =>

    val column = x._1
    val value = x._2

    val parts = value.split(";~;") // Some Super uncommon string that hopefully people will never search for.

    val filterValue = parts(0)
    val filterOperator = if(parts.length >= 2) parts(1) else "eq"

    (column, Filter(filterValue, filterOperator match {
      case "eq" => Equal
      case "lt" => LessThan
      case "lte" => LessThanOrEqual
      case "gt" => GreaterThan
      case "gte" => GreaterThanOrEqual
      case "ne" => NotEqual
    }))
  }
}