//设置package包名称以及导入依赖的类
package com.flipkart.connekt.commons.utils

import kafka.consumer.ConsumerTimeoutException

import scala.collection.{AbstractIterator, Iterator}

object CollectionUtils {

  implicit class iteratorUtils[T](iterators: List[Iterator[T]]) {
    def merge = new AbstractIterator[T] {

      private var inUseItrIndex = 0
      private val iteratorSize = iterators.size

      private def unsafeHasNext(index: Int) = try { iterators(index).hasNext } catch { case _: ConsumerTimeoutException => false }

      override def hasNext: Boolean = {
        if (iterators.nonEmpty) {
          inUseItrIndex = (1 + inUseItrIndex) % iteratorSize

          unsafeHasNext(inUseItrIndex) || {
            def r(stopIdx: Int): Boolean = {
              inUseItrIndex = (1 + inUseItrIndex) % iteratorSize

              if (stopIdx != inUseItrIndex) {
                unsafeHasNext(inUseItrIndex) || r(stopIdx)
              } else false
            }

            r(inUseItrIndex)
          }
        } else false
      }

      override def next(): T = {
        if(iterators.nonEmpty)
          iterators(inUseItrIndex).next()
        else
          Iterator.empty.next()
      }
    }
  }

} 

//设置package包名称以及导入依赖的类
package scawrap

import scala.collection.Iterator
import scala.scalajs.js

import js.annotation.ScalaJSDefined

@ScalaJSDefined
private[scawrap] class WrapIterator[A](
    private val underlying: Iterator[A]) extends js.Iterator[js.UndefOr[A]] {

  def next(): js.Iterator.Entry[js.UndefOr[A]] = {
    if (underlying.hasNext) {
      new js.Iterator.Entry[js.UndefOr[A]] {
        val done: Boolean = false
        val value = js.defined(underlying.next())
      }
    } else {
      new js.Iterator.Entry[js.UndefOr[A]] {
        val done: Boolean = true
        val value: js.UndefOr[Nothing] = js.undefined
      }
    }
  }
}