リトライハンドラー 魔改造

readme.md

try {
  val res = retry(...) {
    ...
  }
} catch {
  case RetryException(es) => ...
}

じゃなく

val res = retry(...) {
  ...
} `catch` {
  case es =>
}

と書けるように魔改造してみた

gistfile1.scala

object RetryUtil {

  import scala.util.control.Exception.allCatch

  case class RetryResult[T](e: Either[List[Throwable], T]) {
    def `catch`(f: List[Throwable] => T): T = e match {
      case Right(r) => r
      case Left(l) => f(l)
    }
  }

  def retry[T](retryLimit: Int)(f: => T): RetryResult[T] =
    retry(retryLimit, 0, classOf[Throwable])(f)

  def retry[T](retryLimit: Int, retryInterval: Int)(f: => T): RetryResult[T] =
    retry(retryLimit, retryInterval, classOf[Throwable])(f)

  def retry[T](retryLimit: Int, catchExceptionClasses: Class[_]*)(f: => T): RetryResult[T] =
    retry(retryLimit, 0, e => catchExceptionClasses.exists(_.isAssignableFrom(e.getClass)))(f)

  def retry[T](retryLimit: Int, shouldCatch: Throwable => Boolean)(f: => T): RetryResult[T] =
    retry(retryLimit, 0, shouldCatch)(f)

  def retry[T](retryLimit: Int, retryInterval: Int, catchExceptionClasses: Class[_]*)(f: => T): RetryResult[T] =
    retry(retryLimit, retryInterval, e => catchExceptionClasses.exists(_.isAssignableFrom(e.getClass)))(f)

  def retry[T](retryLimit: Int, retryInterval: Int, shouldCatch: Throwable => Boolean)(f: => T): RetryResult[T] = {
    @annotation.tailrec
    def retry0(errors: List[Throwable], f: => T): RetryResult[T] = {
      allCatch.either(f) match {
        case Right(r) => RetryResult(Right(r))
        case Left(e) =>
          if (shouldCatch(e)) {
            if (errors.size < retryLimit - 1) {
              Thread.sleep(retryInterval)
              retry0(e :: errors, f)
            } else {
              RetryResult(Left(e :: errors))
            }
          } else throw e
      }
    }
    retry0(Nil, f)
  }
}