Blog Scalaz - Validation http://blog.joecwu.com/2015/07/scava-scala-scalaz-validation.html

blog-Scala-scalaz-validation-1.scala

case class InvalidArgumentException(msg:String) extends Exception(msg)

case class SearchUsersRequest(keyword: Option[String], userType: Option[Int], maxNum: Option[Int], returnFields: List[String]) {
  def getKeywork() = keyword | {throw InvalidArgumentException("keyword cannot be empyt.")}
  def getUserType() = {
    userType.map{ tp => (1 until 10 contains tp) ? tp | {throw InvalidArgumentException("userType must between 1 to 10.")}} |{ throw InvalidArgumentException("userType cannot be empyt.")}
  }
  def getMaxNum() = maxNum.getOrElse(10)
  def getReturnFields() = (returnFields.length > 0) ? returnFields | {throw InvalidArgumentException("must provide returnFields.")}
}

blog-Scala-scalaz-validation-2.scala

class BaseException(val msg:String) extends Exception(msg)
case class InvalidArgumentException(override val msg:String) extends BaseException(msg)

case class SearchUsersRequest(keyword: Option[String], userType: Option[Int], maxNum: Option[Int], returnFields: List[String]) {
  def getKeyword() = keyword.map{_.successNel[BaseException]} | InvalidArgumentException("keyword cannot be empyt.").failNel[String]
  def getUserType() = userType.map{ tp => (1 until 10 contains tp) ? tp.successNel[BaseException] | InvalidArgumentException("userType must between 1 to 10.").failNel[Int]} | InvalidArgumentException("userType cannot be empyt.").failNel
  def getMaxNum() = maxNum.getOrElse(10).successNel[BaseException]
  def getReturnFields() = (returnFields.length > 0) ? returnFields.successNel[BaseException] | InvalidArgumentException("must provide returnFields.").failNel[List[String]]
  def validate() = {
    ( getKeyword() |@| getUserType() |@| getMaxNum |@| getReturnFields ) { (keyword,userType,maxNum,returnFields) => (keyword,userType,maxNum,returnFields) }
  }
}

object TestApp {
  def run = {
    val reqFail = SearchUsersRequest(none[String],11.some,3.some,List("field1"))
    val reqSuccess = SearchUsersRequest("joe".some,6.some,20.some,List("field1","field2"))
    
    reqSuccess.validate match {
      case scalaz.Success(resp) => resp match {case (keyword,userType,maxNum,fields) => println(s"Got keyword:[$keyword] userType:[$userType] maxNum:[$maxNum] fields:[${fields.mkString(",")}]")}
      case scalaz.Failure(errList) => println(errList.toList.map(_.msg))
    }
    //REPL result for reqSuccess
    //Got keyword:[joe] userType:[6] maxNum:[20] fields:[field1,field2]
    
    //REPL result for reqFail
    //List(keyword cannot be empyt., userType must between 1 to 10.)
    
    // Handle success value directly
    reqSuccess.validate.map{
      case (keyword,userType,maxNum,fields) => println(s"Got keyword:[$keyword] userType:[$userType] maxNum:[$maxNum] fields:[${fields.mkString(",")}]")
    }
  }
}