build.sbt

scalaVersion := "2.11.8"

ibraryDependencies ++= Seq(
  "org.apache.commons" % "commons-lang3" % "3.5"
)

flake.scala

import org.apache.commons.lang3.RandomUtils

sealed abstract class FlakeSalt {
  def getSalt(): Int = RandomUtils.nextInt(0, Int.MaxValue)
}

object FlakeSalt {
  case class Random() extends FlakeSalt {
    override def getSalt(): Int= {
      RandomUtils.nextInt(0, Int.MaxValue)
    }
  }
}

case class Flake(flakeSalt: FlakeSalt = FlakeSalt.Random()){
  private val saltBits = 12L
  private val sequenceBits = 10L
  private val sequenceMask = -1L ^ (-1L << sequenceBits)
  private val timestampShift = sequenceBits + saltBits
  private val saltShift = sequenceBits
  def twepoch = 1451574000000L

  val salt = flakeSalt.getSalt() & 0x3ff  // 10bits
  private var lastTimestamp = 0L
  private var sequence = 0L


  def getNext() = synchronized {
    var timestamp = getCurrentTime()
    val timeOffset = twepoch - timestamp

    if(lastTimestamp == timestamp){
      sequence = (sequence + 1) & sequenceMask
      if(sequence==0){
        println("TilNextMilss...")
        timestamp = tilNextMillis(timestamp)
      }
    } else {
      sequence = 0
    }

    lastTimestamp = timestamp
    ((timestamp - twepoch) << timestampShift) | (salt << saltShift) | sequence
  }
  protected def tilNextMillis(lastTimestamp: Long): Long = {
    var timestamp = getCurrentTime()
    while (timestamp <= lastTimestamp) {
      timestamp = getCurrentTime()
    }
    timestamp
  }
  protected def getCurrentTime() = {
    System.currentTimeMillis()
  }
}