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• Hands-On-Big-Data-Analytics-with-PySpark-master
  • Chapter08
    • ImmutableDataSet.scala
    • ImmutableRDD.scala
    • InheritanceRdd.scala
    • ImmutableDataFrame.scala
    • MultithreadedImmutabilityTest.scala
  • Chapter13
    • PageRankTest.scala
    • VertexAPI.scala
    • EdgeAPI.scala
    • GraphBuilder.scala
    • CreatingGraph.scala
    • CalculateDegreeTest.scala
  • LICENSE
  • Chapter01
    • Chapter 1.ipynb
  • Chapter12
    • IntegrationTesting.scala
    • TestingSparkPre2x.scala
    • MockingDataSources.scala
    • SeparatingLogic.scala
    • BonusVerifier.scala
    • PropertyBasedTesting.scala
  • Chapter10
    • SaveCSV.scala
    • SaveJSON.scala
    • SaveParquet.scala
    • ReUseWithCheckpoint.scala
    • SaveAvro.scala
    • SavePlainText.scala
  • README.md
  • Chapter02
    • Chapter 2.ipynb
  • Chapter05
    • Chapter 5.ipynb
  • Chapter03
    • Chapter 3.ipynb
  • Chapter07
    • ReduceAPI.scala
    • GroupByKey.scala
    • TriggerComputations.scala
    • DeferComputations.scala
    • TriggerComputationsReusingRDD.scala
  • Chapter11
    • ActionsOnPairs.scala
    • AggregateByKey.scala
    • CustomRangePartitioner.scala
    • TransformationsOnPairs.scala
    • UsePartitioner.scala
  • Chapter04
    • Chapter 4.ipynb
  • Chapter06
    • Chapter 6.ipynb
  • Chapter09
    • TestingOperationsThatCausesShuffle.scala
    • DataSetJoins.scala
    • ExecutionPlanForJoins.scala
    • ChangingDesign.scala
    • DetectingShuffle.scala
    • CustomPartitioner.scala
    • DataFrameJoins.scala
    • KeyByTesting.scala

package com.tomekl007.chapter_2

import java.util.concurrent.{CountDownLatch, Executors}

import org.scalatest.FunSuite

import scala.collection.mutable.ListBuffer

class MultithreadedImmutabilityTest extends FunSuite {

  test("warning: race condition with mutability") {
    //given
    var listMutable = new ListBuffer[String]()
    val executors = Executors.newFixedThreadPool(2)
    val latch = new CountDownLatch(2)

    //when
    executors.submit(new Runnable {
      override def run(): Unit = {
        latch.countDown()
        listMutable += "A"
      }
    })

    executors.submit(new Runnable {
      override def run(): Unit = {
        latch.countDown()
        if(!listMutable.contains("A")) {
          listMutable += "A"
        }
      }
    })

    latch.await()

    //then
    //listMutable can have ("A") or ("A","A")

  }

}