update

src/main/scala/com/septech/snowflake4s/Generator.scala

@@ -19,6 +19,6 @@ trait Generator {
 
   def generate(): String
 
-  def generateByBatch(batch: Int): List[String]
+  def bulkGenerate(batch: Int): List[String]
 
 }

src/main/scala/com/septech/snowflake4s/GeneratorModule.scala

@@ -16,16 +16,15 @@
 package com.septech.snowflake4s
 
 import com.google.inject.AbstractModule
-import com.septech.snowflake4s.algorithms.TwitterSnowflake
+import com.septech.snowflake4s.algorithms.Snowflake
 import com.septech.snowflake4s.node.MachineMACAddress
-import com.septech.snowflake4s.node.NodeMachine
 import net.codingwell.scalaguice.ScalaModule
 
 class GeneratorModule extends AbstractModule with ScalaModule {
 
   override def configure() = {
     bind[NodeMachine].to[MachineMACAddress]
-    bind[Generator].to[TwitterSnowflake]
+    bind[Generator].to[Snowflake]
   }
 
 }

src/main/scala/com/septech/snowflake4s/node/NodeMachine.scala → src/main/scala/com/septech/snowflake4s/NodeMachine.scala

@@ -13,7 +13,7 @@
  *
  *
  */
-package com.septech.snowflake4s.node
+package com.septech.snowflake4s
 
 trait NodeMachine {
 

src/main/scala/com/septech/snowflake4s/Snowflake4s.scala

@@ -25,6 +25,6 @@ object Snowflake4s {
   def getGenerator: Generator = defaultInstance
 
   def main(args: Array[String]): Unit = {
-    Snowflake4s.getGenerator.generateByBatch(10).foreach(println)
+    Snowflake4s.getGenerator.bulkGenerate(10).foreach(println)
   }
 }

src/main/scala/com/septech/snowflake4s/algorithms/TwitterSnowflake.scala → src/main/scala/com/septech/snowflake4s/algorithms/Snowflake.scala

@@ -15,6 +15,7 @@
  */
 package com.septech.snowflake4s.algorithms
 
+import java.lang.management.ManagementFactory
 import java.time.Clock
 import java.time.LocalDateTime
 import java.time.Month
@@ -26,17 +27,17 @@ import com.google.inject.Inject
 import com.google.inject.Singleton
 import com.septech.snowflake4s.Generator
 import com.septech.snowflake4s.IdEntity
+import com.septech.snowflake4s.NodeMachine
 import com.septech.snowflake4s.exception.GenerateException
 import com.septech.snowflake4s.exception.InvalidSystemClock
-import com.septech.snowflake4s.node.NodeMachine
 
 import scala.collection.mutable.ListBuffer
 import scala.util.Failure
 import scala.util.Success
 import scala.util.Try
 
 @Singleton
-private[snowflake4s] class TwitterSnowflake @Inject()(nodeIdentifier: NodeMachine) extends Generator {
+private[snowflake4s] class Snowflake @Inject()(nodeIdentifier: NodeMachine) extends Generator {
   /**
     *  This is a Custom Epoch, mean for reference time: October 18, 1989, 16:53:40 UTC -
     *  The date of Galileo Spacecraft was launched to explored Jupiter and its moon from Kennedy Space Center, Florida, US.
@@ -46,11 +47,10 @@ private[snowflake4s] class TwitterSnowflake @Inject()(nodeIdentifier: NodeMachin
     */
   final val GALILEO_LAUNCHED_DATETIME: ZonedDateTime =
     LocalDateTime.of(1989, Month.OCTOBER, 18, 16, 53, 40).atZone(ZoneId.of("US/Eastern"))
-  final val CUSTOM_EPOCH: Long = GALILEO_LAUNCHED_DATETIME.toInstant.toEpochMilli
+  final val EPOCH: Long = GALILEO_LAUNCHED_DATETIME.toInstant.toEpochMilli
 
   private final val STARTING_SEQUENCE_NUMBERS: Int = 1
   private final val lock = new ReentrantLock()
-  private var lastTimestamp: Long = -1L
   private var sequence: Long = 0L
 
   /**
@@ -63,21 +63,21 @@ private[snowflake4s] class TwitterSnowflake @Inject()(nodeIdentifier: NodeMachin
     * - 12 bits that represent an auto-incrementing sequence, modulus 4096.
     *   This means we can generate 4096 IDs, per Node, per millisecond
     */
-  final private val TOTAL_BITS: Int = 64
-  final private val TIMESTAMP_BITS: Int = 41
-  final private val WORKER_BITS: Int = 10 // up to 1024 machine
-  final private val SEQUENCE_BITS: Int = 12 // up to 4096 ids per machine
-  final private val MAX_SEQUENCE_NUMBERS: Int = Math.pow(2, SEQUENCE_BITS).toInt
+  final private val workerIdBits = 5L
+  final private val datacenterIdBits = 5L
+  final private val sequenceBits = 12L
+  final private val workerIdShift = sequenceBits
+  final private val machineIdShift = sequenceBits + workerIdBits
+  final private val timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits
+  final private val sequenceMask = -1L ^ (-1L << sequenceBits)
+  final private var lastTimestamp = -1L
 
-  final private val TIMESTAMP_BITS_SHIFT: Int = TOTAL_BITS - TIMESTAMP_BITS
-  final private val WORKER_ID_BITS_SHIFT: Int = TOTAL_BITS - TIMESTAMP_BITS - SEQUENCE_BITS
-  final private val SEQUENCE_MASK = -1L ^ (-1L << MAX_SEQUENCE_NUMBERS)
+  final private val MACHINE_ID: Long = nodeIdentifier.getId().toLong
+  final private val WORKER_ID: Long = getProcessId
 
-  final private val WORKER_ID: Long = (nodeIdentifier.getId().toLong % MAX_SEQUENCE_NUMBERS) << WORKER_ID_BITS_SHIFT
+  override def generate(): String = bulkGenerate(1).headOption.fold[String](throw new GenerateException)(id => id)
 
-  override def generate(): String = generateByBatch(1).headOption.fold[String](throw new GenerateException)(_ => _)
-
-  override def generateByBatch(batch: Int): List[String] = {
+  override def bulkGenerate(batch: Int): List[String] = {
     lock.lock()
 
     val ids = generateIds(batch).map(_.getString)
@@ -88,14 +88,9 @@ private[snowflake4s] class TwitterSnowflake @Inject()(nodeIdentifier: NodeMachin
 
   private def generateIds(batch: Int): List[IdEntity] = synchronized {
     Try {
-      require(batch <= MAX_SEQUENCE_NUMBERS)
-
-      val currentTimestamp: Long = Clock.systemUTC().millis()
-      val shiftedTimestamp: Long = (currentTimestamp - CUSTOM_EPOCH) << TIMESTAMP_BITS_SHIFT
-
       val ids = new ListBuffer[IdEntity]()
 
-      (STARTING_SEQUENCE_NUMBERS to batch).map(_ => ids += nextId(currentTimestamp, shiftedTimestamp, WORKER_ID))
+      (STARTING_SEQUENCE_NUMBERS to batch).map(_ => ids += nextId())
 
       ids.toList
     }  match {
@@ -104,22 +99,33 @@ private[snowflake4s] class TwitterSnowflake @Inject()(nodeIdentifier: NodeMachin
     }
   }
 
-  private def nextId(currentTimestamp: Long, shiftedTimestamp: Long, workerId: Long): IdEntity = {
-    var timestamp = Clock.systemUTC().millis()
+  private def nextId(): IdEntity = {
+    var currentTimestamp: Long = Clock.systemUTC().millis()
 
-    if (timestamp < lastTimestamp) {
-      val timeDiff = lastTimestamp - timestamp
+    if (currentTimestamp < lastTimestamp) {
+      val timeDiff = lastTimestamp - currentTimestamp
       throw new InvalidSystemClock("Clock moved backwards. Refusing to generate id for %d milliseconds".format(timeDiff))
     }
 
-    if (lastTimestamp == timestamp) {
-      sequence = (sequence + 1) & SEQUENCE_MASK
-      if (sequence == 0) timestamp = nextMillis(lastTimestamp)
-    } else sequence = 0
+    if (lastTimestamp == currentTimestamp) {
+      sequence = (sequence + 1) & sequenceMask
 
-    lastTimestamp = timestamp
+      if (sequence == 0) {
+        currentTimestamp = nextMillis(lastTimestamp)
+      }
+    } else{
+      sequence = 0
+    }
 
-    IdEntity(shiftedTimestamp | workerId | sequence)
+    lastTimestamp = currentTimestamp
+
+    val id =
+      ((currentTimestamp - EPOCH) << timestampLeftShift) |
+      (MACHINE_ID << machineIdShift) |
+      (WORKER_ID << workerIdShift) |
+      sequence
+
+    IdEntity(Math.abs(id))
   }
 
   private def nextMillis(lastTimestamp: Long): Long = {
@@ -130,4 +136,8 @@ private[snowflake4s] class TwitterSnowflake @Inject()(nodeIdentifier: NodeMachin
     timestamp
   }
 
+  protected[snowflake4s] def getProcessId: Long = {
+    ManagementFactory.getRuntimeMXBean.getName.split("@").headOption.map(_.toLong).fold(throw new Exception)(pid => pid)
+  }
+
 }

src/main/scala/com/septech/snowflake4s/node/MachineMACAddress.scala

@@ -17,6 +17,7 @@ package com.septech.snowflake4s.node
 
 import java.net._
 
+import com.septech.snowflake4s.NodeMachine
 import com.septech.snowflake4s.exception.MacAddressException
 
 import scala.util.Failure
@@ -30,10 +31,9 @@ private[snowflake4s] class MachineMACAddress extends NodeMachine {
 
     localNetworkInterface
       .getHardwareAddress.toList
-      .map(b => String.format("%02x", b.asInstanceOf[Object]))
-      .map(Integer.parseInt(_, 16)).foldLeft(0L) {
-        case (acc, item) => acc * 256 + item
-      }.toString
+      .map(byte => Integer.parseInt(String.format("%02x", byte.asInstanceOf[Object]), 16))
+      .foldLeft(0L) { case (acc, item) => acc * 256 + item }
+      .toString
   } match {
     case Failure(_) => throw new MacAddressException()
     case Success(address) => address