Scala Random类代码示例

//设置package包名称以及导入依赖的类
package com.rockiey.kafka

import java.util.{Date, Properties, Random}

import kafka.producer.{KeyedMessage, Producer, ProducerConfig}
import org.junit.{After, Before, Test}

class TestProducer {

  val brokers = "localhost:9092"
  val topic = "test"

  val rnd = new Random()
  val props = new Properties()
  props.put("metadata.broker.list", brokers)
  props.put("serializer.class", "kafka.serializer.StringEncoder")
  //props.put("partitioner.class", "com.colobu.kafka.SimplePartitioner")
  props.put("producer.type", "async")
  //props.put("request.required.acks", "1")

  var producer: Producer[String, String] = null

  @Before
  def before: Unit = {

    val config = new ProducerConfig(props)
    producer = new Producer[String, String](config)
  }

  @After
  def after: Unit = {
    producer.close()
  }

  def produce(events: Int): Unit = {
    val t = System.currentTimeMillis()
    for (nEvents <- Range(0, events)) {
      val runtime = new Date().getTime()
      val ip = "192.168.2." + rnd.nextInt(255)
      val msg = runtime + "," + nEvents + ",www.example.com," + ip
      val data = new KeyedMessage[String, String](topic, ip, msg)
      producer.send(data)
    }

    System.out.println("sent per second: " + events * 1000 / (System.currentTimeMillis() - t))
  }

  @Test
  def testProducer: Unit = {
    produce(100)
  }

  @Test
  def testConsumer {

  }
} 

//设置package包名称以及导入依赖的类
package xyz.domi1819.invisiblights

import java.util.Random

import net.minecraft.block.Block
import net.minecraft.block.material.Material
import net.minecraft.creativetab.CreativeTabs
import net.minecraft.init.Items
import net.minecraft.item.Item
import net.minecraft.util.AxisAlignedBB
import net.minecraft.world.{IBlockAccess, World}

class BlockLightSource extends Block(Material.circuits) {
  var visibleFlag = false
  setHardness(0.1F)
  setResistance(0.1F)
  setLightLevel(1)
  setCreativeTab(CreativeTabs.tabRedstone)
  setBlockName("blockLightSource")
  setBlockTextureName("invisiblights:light")
  setBlockUnbreakable()

  override def getSelectedBoundingBoxFromPool(world: World, x: Int, y: Int, z: Int): AxisAlignedBB = {
    setBlockBoundsBasedOnState(world, x, y, z)
    if (visibleFlag) AxisAlignedBB.getBoundingBox(x, y, z, x + 1, y + 1, z + 1)
    else AxisAlignedBB.getBoundingBox(0, 0, 0, 0, 0, 0)
  }

  override def setBlockBoundsBasedOnState(world: IBlockAccess, x: Int, y: Int, z: Int) {
    if (visibleFlag) setBlockBounds(0, 0, 0, 1, 1, 1)
    else setBlockBounds(0, 0, 0, 0, 0, 0)
  }

  override def getCollisionBoundingBoxFromPool(world: World, x: Int, y: Int, z: Int): AxisAlignedBB = {
    setBlockBoundsBasedOnState(world, x, y, z)
    null
  }

  override def isReplaceable(world: IBlockAccess, x: Int, y: Int, z: Int): Boolean = true

  override def getItemDropped(i: Int, random: Random, j: Int): Item = Items.glowstone_dust

  override def getRenderBlockPass: Int = 1

  override def quantityDropped(rand: Random): Int = 0

  override def isOpaqueCube: Boolean = false

  override def shouldSideBeRendered(world: IBlockAccess, x: Int, y: Int, z: Int, side: Int): Boolean = world.getBlock(x, y, z) != this
} 

//设置package包名称以及导入依赖的类
package conf.security

import java.security.SecureRandom
import java.util.Random
import javax.crypto.SecretKeyFactory
import javax.crypto.spec.PBEKeySpec

import base64.Decode.{apply => fromBase64, urlSafe => fromBase64UrlSafe}
import base64.Encode.{apply => toBase64, urlSafe => toBase64UrlSafe}
import com.github.t3hnar.bcrypt._
import org.apache.commons.lang3.RandomStringUtils


      def slowEquals(a: Array[Byte], b: Array[Byte]): Boolean = {
        var diff = a.length ^ b.length;
        for (i <- 0 until math.min(a.length, b.length)) diff |= a(i) ^ b(i)
        return diff == 0
      }
      val hashParts = hashedPassword.split(HashPartSeparator)
      if (hashParts.length != 3) return false
      if (!hashParts(0).forall(_.isDigit)) return false
      val nrOfIterations = hashParts(0).toInt // this will throw a NumberFormatException for non-Int numbers...
      val hash = fromBase64UrlSafe(hashParts(1))
      val salt = fromBase64UrlSafe(hashParts(2))
      if (hash.isLeft || salt.isLeft) return false
      if (hash.right.get.length == 0 || salt.right.get.length == 0) return false
      val calculatedHash = pbkdf2(password, salt.right.get, nrOfIterations)
      slowEquals(calculatedHash, hash.right.get)
    }

    private def pbkdf2(password: String, salt: Array[Byte], nrOfIterations: Int): Array[Byte] = {
      val keySpec = new PBEKeySpec(password.toCharArray(), salt, nrOfIterations, SizeOfPasswordHashInBytes * 8)
      val keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1")
      keyFactory.generateSecret(keySpec).getEncoded()
    }

    private def generateRandomBytes(length: Int): Array[Byte] = {
      val keyData = new Array[Byte](length)
      RandomSource.nextBytes(keyData)
      keyData
    }

    override def hashAuth(key: String): String = {
      hashPassword(key)
    }

    override def hashCheck(key: String, hash: String): Boolean = {
      validatePassword(key, hash)
    }
  }
} 

//设置package包名称以及导入依赖的类
package conf.util

import java.util.Random

import org.apache.commons.lang3.RandomStringUtils


object Util {

  import java.net._

  def md5Hash(text: String): String = {
    val hash = text + InetAddress.getLocalHost.getHostName
    java.security.MessageDigest.getInstance("MD5").digest(hash.getBytes()).map(0xFF & _).map {
      "%02x".format(_)
    }.foldLeft("") {
      _ + _
    }
  }


  private def generateOrganisationCode(name: String): String = {
    val count: Int = 4
    val useLetters: Boolean = true
    val useNumbers: Boolean = false
    val choseFrom = name.toCharArray
    RandomStringUtils.random(count, 0, 0, useLetters, useNumbers, choseFrom, new Random())
  }

  private def getSalt(): String = {
    val length: Int = 5
    val useLetters: Boolean = true
    val useNumbers: Boolean = true
    RandomStringUtils.random(length, useLetters, useNumbers)
  }

  def codeGen(name: String): String = {
    val code = generateOrganisationCode(name)
      .toCharArray
      .sortWith(_ < _)
      .mkString("").toUpperCase

    val salt = getSalt()
      .toCharArray
      .sortWith(_ < _)
      .mkString("").toUpperCase
    (code + "-" + salt)
  }
} 

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

import java.io.PrintWriter
import java.net.ServerSocket

import scala.collection.mutable


object T02_RandomLogger {

  def generateContent(index: Int): String = {
    import scala.collection.mutable.ListBuffer
    var charList = ListBuffer[Char]()
    for (i <- 65 to 90) {
      charList += i.toChar
    }
    val charArray = charList.toArray
    charArray(index).toString
  }

  def index = {
    import java.util.Random
    val rand = new Random
    rand.nextInt(7)
  }

  def main(args: Array[String]) {
    var port = 9999
    var sec = 1000l
    val map = new mutable.HashMap[String,Int]()
    if (args.length >= 2) {
      port = args(0).toInt
      sec = args(1).toLong
    }
    println("listening:" + port)
    val listener = new ServerSocket(port)
    while (true) {
      println("waiting...")
      val socket = listener.accept()
      println("accept:" + socket)
      new Thread() {
        override def run = {
          println("got client:" + socket.getInetAddress)
          val out = new PrintWriter(socket.getOutputStream, true)
          while (true) {
            Thread.sleep(sec)
            val content = generateContent(index)
            map.put(content,map.getOrElse(content,0)+1);
            out.write(content+"\n")
            out.flush()
            println(map)
          }
          socket.close()
        }
      }.start()
    }
  }
} 

//设置package包名称以及导入依赖的类
package net.shiroka.cat
import java.util.Random
import scala.collection.JavaConverters._
import akka.actor._
import com.typesafe.config.ConfigFactory

object Main {
  val roles = ConfigFactory.load.getConfig("akka.cluster").getStringList("roles").asScala
  val primaryRole: String = roles.headOption.getOrElse(sys.error("empty roles"))

  def main(args: Array[String]): Unit = {
    implicit lazy val system = ActorSystem("cluster")

    primaryRole match {
      case "seed" =>
        Cat.startProxy

      case "sensor" =>
        Cat.startProxy
        system.actorOf(Props(classOf[Sensor], new Random()), "cat")

      case "cat" =>
        Cat.startSharding
        journal.RedisSweeper.startSingleton("redis-sweeper", Some("cat"))

      case role => sys.error(s"Unexpected role $role")
    }

    Profiler.run(system)
    TinyHttpServer.serve(8080)
  }
} 

//设置package包名称以及导入依赖的类
package net.shiroka.cat

import java.util.Random
import scala.concurrent.duration._
import scala.concurrent.ExecutionContext
import akka.actor._
import akka.cluster._
import akka.cluster.sharding._
import akka.cluster.ClusterEvent._
import net.ceedubs.ficus.Ficus._
import pb.cat.Meow

class Sensor(val random: Random = new Random()) extends Actor {
  import Sensor._

  implicit val ec: ExecutionContext = context.dispatcher
  private var started: Option[Cancellable] = None

  val system = context.system
  val cat = ClusterSharding(context.system).shardRegion(Cat.shardingName)
  val cluster = Cluster(context.system)

  override def preStart(): Unit = cluster.subscribe(self, classOf[MemberUp], classOf[MemberEvent])
  override def postStop(): Unit = cluster.unsubscribe(self)

  def receive = {
    case Sense => (0 until batchSize).foreach(_ =>
      cat ! Meow(randomCatId, System.currentTimeMillis() / 1000L))
    case state: CurrentClusterState =>
      state.members
        .find(member => member.status == MemberStatus.Up && member.address == cluster.selfAddress)
        .foreach(_ => self ! Start)
    case MemberUp(member) =>
      if (member.address == cluster.selfAddress) { self ! Start }
    case msg: MemberEvent =>
      if (cluster.state.unreachable.size == 0) { self ! Start }
      else { stop }
    case Start => start
  }

  private def stop: Unit = {
    this.started.foreach(_.cancel)
    this.started = None
  }

  private def start: Unit =
    if (started.isEmpty) {
      this.started = Some(system.scheduler.schedule(2.seconds, interval, self, Sense))
    }

  private def randomCatId: String = s"cat-${random.nextInt(Cat.maxEntities)}"
}

object Sensor extends Config {
  val configKey = "sensor"
  val interval = config.as[FiniteDuration]("interval")
  val batchSize = config.as[Int]("batch.size")
  object Start
  object Sense
} 

//设置package包名称以及导入依赖的类
package com.malaska.spark.training.streaming.dstream.sessionization

import java.io.BufferedWriter
import java.io.FileWriter
import org.apache.hadoop.fs.FileSystem
import org.apache.hadoop.conf.Configuration
import java.io.OutputStreamWriter
import org.apache.hadoop.fs.Path
import java.util.Random

object SessionDataFileHDFSWriter {
  
  val eol = System.getProperty("line.separator");  
  
  def main(args: Array[String]) {
    if (args.length == 0) {
        println("SessionDataFileWriter {tempDir} {distDir} {numberOfFiles} {numberOfEventsPerFile} {waitBetweenFiles}");
        return;
    }
    val conf = new Configuration
    conf.addResource(new Path("/etc/hadoop/conf/core-site.xml"))
    conf.addResource(new Path("/etc/hadoop/conf/mapred-site.xml"))
    conf.addResource(new Path("/etc/hadoop/conf/hdfs-site.xml"))
    
    val fs = FileSystem.get(new Configuration)
    val rootTempDir = args(0)
    val rootDistDir = args(1)
    val files = args(2).toInt
    val loops = args(3).toInt
    val waitBetweenFiles = args(4).toInt
    val r = new Random
    for (f <- 1 to files) {
      val rootName = "/weblog." + System.currentTimeMillis()
      val tmpPath = new Path(rootTempDir + rootName + ".tmp")
      val writer = new BufferedWriter(new OutputStreamWriter(fs.create(tmpPath)))
      
      print(f + ": [")
      
      val randomLoops = loops + r.nextInt(loops)
      
      for (i <- 1 to randomLoops) {
        writer.write(SessionDataGenerator.getNextEvent + eol)
        if (i%100 == 0) {
          print(".")
        }
      }
      println("]")
      writer.close
      
      val distPath = new Path(rootDistDir + rootName + ".dat")
      
      fs.rename(tmpPath, distPath)
      Thread.sleep(waitBetweenFiles)
    }
    println("Done")
  }
} 

//设置package包名称以及导入依赖的类
package com.malaska.spark.training.salted

import java.util.Random

import org.apache.log4j.{Level, Logger}
import org.apache.spark.sql.SparkSession

object SaltedExample {
  Logger.getLogger("org").setLevel(Level.OFF)
  Logger.getLogger("akka").setLevel(Level.OFF)

  def main(args:Array[String]): Unit = {

    val jsonPath = args(0)

    val sparkSession = SparkSession.builder
      .master("local")
      .appName("my-spark-app")
      .config("spark.some.config.option", "config-value")
      .getOrCreate()

    val jsonDfLeft = sparkSession.read.json(jsonPath)

    val saltedLeft = jsonDfLeft.rdd.flatMap(r => {
      val group = r.getAs[String]("group")
      val value = r.getAs[Long]("value")

      Seq((group + "_" + 0, value),(group + "_" + 1, value))
    })

    val jsonDfRight = sparkSession.read.json(jsonPath)

    val saltedRight = jsonDfRight.rdd.mapPartitions(it => {

      val random = new Random()

      it.map(r => {
        val group = r.getAs[String]("group")
        val value = r.getAs[Long]("value")

        (group + "_" + random.nextInt(2), value)
      })
    })

    jsonDfLeft.join(jsonDfRight).collect().foreach(r => {
      println("Normal.result:" + r)
    })
    println("----")
    saltedLeft.join(saltedRight).collect().foreach(r => {
      println("Salted.result:" + r)
    })
  }
} 

//设置package包名称以及导入依赖的类
package com.malaska.spark.training.partitioning

import java.util.Random

import org.apache.spark.Partitioner


class AppleCustomPartitioner(numOfParts:Int) extends Partitioner {
  override def numPartitions: Int = numOfParts
  def random = new Random()

  override def getPartition(key: Any): Int = {
    val k = key.asInstanceOf[(String, Long)]
    val ticker = k._1
    if (ticker.equals("apple")) {
      val saltedTicker = ticker + random.nextInt(9)
      Math.abs(saltedTicker.hashCode) % numPartitions
    } else {
      Math.abs(ticker.hashCode) % numPartitions
    }
  }
} 

//设置package包名称以及导入依赖的类
package edu.neu.coe.scala.ga

package rng

import java.util.Random

trait RNG[+A] {
  def next: RNG[A]
  def value: A
}

abstract class RNG_Java[+A](n: Long) extends RNG[A] { 
  // must be overridden by sub-classes
  def value: A
  def newRNG(n: Long): RNG[A]
  // may be overridden (if you want to define your own pseudo-random sequence)
  def nextSeed: Long = RNG_Java.nextSeed(n)
  // base method -- not normally overridden
  def next: RNG[A] = newRNG(nextSeed)
  def state = n
}

object RNG_Java {
  def nextSeed(n: Long): Long = new Random(n).nextLong
}

case class LongRNG(n: Long) extends RNG_Java[Long](n) {
  def newRNG(n: Long): RNG[Long] = LongRNG(n) 
  def value = n 
}

case class DoubleRNG(n: Long) extends RNG_Java[Double](n) {
  def newRNG(n: Long) = DoubleRNG(n) 
  def value = n.toDouble/Long.MaxValue
  override def toString = s"DoubleRNG: $n->$value"
}


case class UniformDouble(x: Double) extends AnyVal with Ordered[UniformDouble] {
    def + (y: Double) = x + y
    def compare(that: UniformDouble): Int = x.compare(that.x)
}

object DoubleRNG {
  def apply: RNG[Double] = DoubleRNG(System.currentTimeMillis())
}

object UniformDoubleRNG {
  def apply: RNG[UniformDouble] = UniformDoubleRNG(System.currentTimeMillis())
  implicit val u: Unit = Unit
}

object GaussianRNG {
  def apply: RNG[(Double,Double)] = GaussianRNG(System.currentTimeMillis())
}

object UniformDouble {
  def create(x: Double)(implicit y: Unit) = if (x>=0 && x<=1) new UniformDouble(x) else throw new IllegalArgumentException(s"$x is not in range 0..1")
  def + (x: Double, y: UniformDouble) = y+x
} 

//设置package包名称以及导入依赖的类
package edu.neu.coe.scala

package rng

import java.util.Random

trait RNG[+A] {
  def next: RNG[A]
  def value: A
}

abstract class RNG_Java[+A](n: Long) extends RNG[A] { 
  // must be overridden by sub-classes
  def value: A
  def newRNG(n: Long): RNG[A]
  // may be overridden (if you want to define your own pseudo-random sequence)
  def nextSeed: Long = RNG_Java.nextSeed(n)
  // base method -- not normally overridden
  def next: RNG[A] = newRNG(nextSeed)
  def state = n
}

object RNG_Java {
  def nextSeed(n: Long): Long = new Random(n).nextLong
}

case class LongRNG(n: Long) extends RNG_Java[Long](n) {
  def newRNG(n: Long): RNG[Long] = ???
  def value = ???
}

case class DoubleRNG(n: Long) extends RNG_Java[Double](n) {
  def newRNG(n: Long) = ???
  def value = ???
  override def toString = s"DoubleRNG: $n->$value"
}


case class UniformDouble(x: Double) extends AnyVal {
    def + (y: Double) = x + y
}

object UniformDoubleRNG {
  def apply: RNG[UniformDouble] = UniformDoubleRNG(System.currentTimeMillis())
}

object GaussianRNG {
  def apply: RNG[(Double,Double)] = GaussianRNG(System.currentTimeMillis())
}

object UniformDouble {
  def apply(x: Double, y: Unit) = if (x>=0 && x<=1) new UniformDouble(x) else throw new IllegalArgumentException(s"$x is not in range 0..1")
  def + (x: Double, y: UniformDouble) = y+x
} 

//设置package包名称以及导入依赖的类
package soal.ppr

import java.util.Random

import co.teapot.tempest.graph.ConcurrentHashMapDynamicGraph
import org.scalatest.{FlatSpec, Matchers}

import scala.collection.mutable
import scala.io.Source

class BidirectionalPPREstimatorSpec extends FlatSpec with Matchers {
  val graph = ConcurrentHashMapDynamicGraph.readGraph("src/test/resources/test_graph.txt")
  val teleportProb = 0.2f
  val random = new Random(2) // Seed for consistent tests
  val estimator = new BidirectionalPPREstimator(graph, teleportProb, random)
  val truePPRs = BidirectionalPPREstimatorSpec.testGraphTruePPRs

  "BidirectionalPPRSearcher.estimateInversePPR" should "be correct on the test graph" in {
    val pprErrorTolerance = 2.0e-6f
    for (((s, t), truePPR) <- truePPRs) {
      val inversePPRs = estimator.estimatePPRToTarget(t, pprErrorTolerance)
      withClue (s"Testing Pair ($s, $t)") {
        inversePPRs(s) should equal (truePPR +- pprErrorTolerance)
      }
    }
  }

  "BidirectionalPPRSearcher.estimatePPR" should "be correct on the test graph" in {
    val relativeError = 0.01f
    val stPairs = Array(0 -> 1, 2 -> 3, 5 -> 9, 0 -> 0)

    for ((s, t) <- stPairs) {
      withClue (s"Testing Pair ($s, $t)") {
        estimator.estimatePPRSingleSource(s, t, 0.03f, relativeError) should equal (
          truePPRs((s, t)) +- truePPRs((s, t)) * relativeError * 2)
      }
    }
  }
}

object BidirectionalPPREstimatorSpec {
  def testGraphTruePPRs: collection.Map[(Int, Int), Float] = {
    val pprMap = new mutable.HashMap[(Int, Int), Float] {
      override def default(key: (Int, Int)) = 0.0f
    }
    for (line <- Source.fromFile("src/test/resources/test_graph_true_pprs.txt").getLines()) {
      val pieces = line.split("\t")
      val (startId, targetId, truePPR) = (pieces(0).toInt, pieces(1).toInt, pieces(2).toFloat)
      pprMap((startId, targetId)) = truePPR
    }
    pprMap
  }
} 

//设置package包名称以及导入依赖的类
package soal.util

import java.util.Random

import org.scalatest.{FlatSpec, Matchers}



class DiscreteAliasSamplerSpec  extends FlatSpec with Matchers  {
  val random = new Random(1)
  def testDistribution(unnormalizedProbabilities: Array[Float],
                       values: Seq[Int],
                       nSamples: Int = 10000
      ): Unit = {
    val probabilities = unnormalizedProbabilities map { _ / unnormalizedProbabilities.sum }
    val n = unnormalizedProbabilities.size
    val valueToIndex = (values zip (0 until n)).toMap
    val sampler = new DiscreteAliasSampler(values, unnormalizedProbabilities, random)
    val sampleCounts = Array.fill(n)(0)
    val tol = 4.0f / math.sqrt(nSamples).toFloat
    for (i <- 0 until nSamples) {
      val v = sampler.sample()
      sampleCounts(valueToIndex(v)) += 1
    }
    for (i <- 0 until n) {
      sampleCounts(i).toFloat / nSamples should equal (probabilities(i) +- tol)
    }

    def f(v: Int): Float = v.toFloat * v.toFloat // compute expectation of v => v^2
    val trueExpectation = ((probabilities zip values) map { case (p, v) => p * v * v }).sum
    sampler.expectation(f) shouldEqual (trueExpectation +- trueExpectation * 1.00001f)
  }

  "A Discrete Distribution" should "support sampling" in {
    testDistribution(Array(575.6355f, 89.733475f, 86.90718f, 721.26416f), Array(2, 3, 5, 7))
    testDistribution(Array(2.0f, 5.0f, 3.0f), Array(17, 11, 13))
    testDistribution(Array(1.0f, 1.0f, 1.0f, 1.0f), Array(-2, 3, -5, 7))
    testDistribution(Array(0.9f, 0.1f), Array(19, 17))
    an[IllegalArgumentException] should be thrownBy {
      new DiscreteAliasSampler(Array(1), Array(1.0f, 2.0f))
    }
  }
} 

//设置package包名称以及导入依赖的类
package xyztr

import java.security.SecureRandom
import java.util.Random

import org.jboss.netty.util.CharsetUtil
import org.scalatest.{FlatSpec, Matchers}

class RandomTest extends FlatSpec with Matchers {
  "SecureRandom" should "generate completely random numbers by default" in {
    val rg = new SecureRandom()
    val randomLong = rg.nextLong
    randomLong should not be 606409227870597303L
  }

  "SecureRandom" should "generate completely random numbers even if the same seed is used" in {
    val seed = new String("seed").getBytes(CharsetUtil.UTF_8)
    val rg1 = new SecureRandom()
    val rg2 = new SecureRandom()
    rg1.setSeed(seed)
    rg2.setSeed(seed)

    val b1 = Crypto.toBytes(1, 2, 3, 4, 5, 6, 7, 8)
    val b2 = Crypto.toBytes(1, 2, 3, 4, 5, 6, 7, 8)
    rg1.nextBytes(b1)
    rg2.nextBytes(b2)
    b1 should not be b2
  }

  "Random" should "generate completely non-random numbers if the same seed is used" in {
    val seed = 77
    val rg1 = new Random(seed)
    val rg2 = new Random(seed)

    val b1 = Crypto.toBytes(1, 2, 3, 4, 5, 6, 7, 8)
    val b2 = Crypto.toBytes(1, 2, 3, 4, 5, 6, 7, 8)
    rg1.nextBytes(b1)
    rg2.nextBytes(b2)
    b1 should be(b2)
  }
}