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roshane/validation-engine.scala

Last active June 20, 2019 15:50
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  1. roshane renamed this gist Jun 20, 2019. 1 changed file with 0 additions and 0 deletions.
    0 validation-engine → validation-engine.scala
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  2. roshane renamed this gist Jun 20, 2019. 1 changed file with 0 additions and 0 deletions.
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  3. roshane created this gist Jun 20, 2019.
    72 changes: 72 additions & 0 deletions scala
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    import scala.concurrent.Future

    import scala.concurrent.ExecutionContext.Implicits.global

    trait Request
    case class AdhocCreateRequest(name: String) extends Request
    case class RegularCreateRequest(name: String) extends Request

    class Repository {
    def doSomething = println("hello from repository")
    }

    abstract class ValidationRule[T] {
    def isSupported(t: T): Boolean
    def validate(t: T): Future[Unit]
    }

    class RootValidationRule[T](val maybeSuccessor: Option[ValidationRule[T]])
    extends ValidationRule[T] {
    def isSupported(t: T): Boolean = true
    def validate(t: T): Future[Unit] = maybeSuccessor.fold(Future.unit)(_.validate(t))
    }

    class FieldValidationRule[T](val maybeSuccessor: Option[ValidationRule[T]])
    extends ValidationRule[T] {

    def isSupported(t: T): Boolean = t.getClass() == classOf[AdhocCreateRequest]

    def validate(t: T): Future[Unit] = isSupported(t) match {
    case true =>
    println(s"validating request $t")
    val request = t.asInstanceOf[AdhocCreateRequest]
    Future {}
    case _ => maybeSuccessor.fold(Future.unit)(_.validate(t))
    }
    }

    class OverlapValidationRule[T](val maybeSuccessor: Option[ValidationRule[T]])(implicit repository: Repository)
    extends ValidationRule[T] {
    def isSupported(t: T): Boolean = t.getClass() == classOf[RegularCreateRequest]

    def validate(t: T): Future[Unit] = isSupported(t) match {
    case true =>
    println(s"validating request $t")
    val request = t.asInstanceOf[RegularCreateRequest]
    Future {
    repository.doSomething
    throw new Exception("Invalid request is overlapping")
    }

    case _ =>
    println(s"$t skipping ${classOf[OverlapValidationRule[T]]}")
    maybeSuccessor.fold(Future.unit)(_.validate(t))
    }
    }

    object ValidationEngine extends App {

    implicit val repository = new Repository

    val fieldValidationRule = new FieldValidationRule[Request](None)
    val overlapValidationRule = new OverlapValidationRule[Request](Some(fieldValidationRule))
    val rootValidationRule = new RootValidationRule(Some(overlapValidationRule))

    val adhocCreate = AdhocCreateRequest("create adhoc schedule")
    val regularCreate = RegularCreateRequest("create regular schedule")

    rootValidationRule.validate(adhocCreate)
    rootValidationRule.validate(regularCreate)

    }