KAFKA-1818 KAFKA-1818 clean up code to more idiomatic scala usage; reviewed by Neha Narkhede and Gwen Shapira

core/src/main/scala/kafka/utils/ReplicationUtils.scala

@@ -61,30 +61,22 @@ object ReplicationUtils extends Logging {
 
   def getLeaderIsrAndEpochForPartition(zkClient: ZkClient, topic: String, partition: Int):Option[LeaderIsrAndControllerEpoch] = {
     val leaderAndIsrPath = ZkUtils.getTopicPartitionLeaderAndIsrPath(topic, partition)
-    val leaderAndIsrInfo = ZkUtils.readDataMaybeNull(zkClient, leaderAndIsrPath)
-    val leaderAndIsrOpt = leaderAndIsrInfo._1
-    val stat = leaderAndIsrInfo._2
-    leaderAndIsrOpt match {
-      case Some(leaderAndIsrStr) => parseLeaderAndIsr(leaderAndIsrStr, leaderAndIsrPath, stat)
-      case None => None
-    }
+    val (leaderAndIsrOpt, stat) = ZkUtils.readDataMaybeNull(zkClient, leaderAndIsrPath)
+    leaderAndIsrOpt.flatMap(leaderAndIsrStr => parseLeaderAndIsr(leaderAndIsrStr, leaderAndIsrPath, stat))
   }
 
   private def parseLeaderAndIsr(leaderAndIsrStr: String, path: String, stat: Stat)
       : Option[LeaderIsrAndControllerEpoch] = {
-    Json.parseFull(leaderAndIsrStr) match {
-      case Some(m) =>
-        val leaderIsrAndEpochInfo = m.asInstanceOf[Map[String, Any]]
-        val leader = leaderIsrAndEpochInfo.get("leader").get.asInstanceOf[Int]
-        val epoch = leaderIsrAndEpochInfo.get("leader_epoch").get.asInstanceOf[Int]
-        val isr = leaderIsrAndEpochInfo.get("isr").get.asInstanceOf[List[Int]]
-        val controllerEpoch = leaderIsrAndEpochInfo.get("controller_epoch").get.asInstanceOf[Int]
-        val zkPathVersion = stat.getVersion
-        debug("Leader %d, Epoch %d, Isr %s, Zk path version %d for leaderAndIsrPath %s".format(leader, epoch,
-          isr.toString(), zkPathVersion, path))
-        Some(LeaderIsrAndControllerEpoch(LeaderAndIsr(leader, epoch, isr, zkPathVersion), controllerEpoch))
-      case None => None
-    }
+    Json.parseFull(leaderAndIsrStr).flatMap {m =>
+      val leaderIsrAndEpochInfo = m.asInstanceOf[Map[String, Any]]
+      val leader = leaderIsrAndEpochInfo.get("leader").get.asInstanceOf[Int]
+      val epoch = leaderIsrAndEpochInfo.get("leader_epoch").get.asInstanceOf[Int]
+      val isr = leaderIsrAndEpochInfo.get("isr").get.asInstanceOf[List[Int]]
+      val controllerEpoch = leaderIsrAndEpochInfo.get("controller_epoch").get.asInstanceOf[Int]
+      val zkPathVersion = stat.getVersion
+      debug("Leader %d, Epoch %d, Isr %s, Zk path version %d for leaderAndIsrPath %s".format(leader, epoch,
+        isr.toString(), zkPathVersion, path))
+      Some(LeaderIsrAndControllerEpoch(LeaderAndIsr(leader, epoch, isr, zkPathVersion), controllerEpoch))}
   }
 
 }

core/src/test/scala/unit/kafka/utils/ReplicationUtilsTest.scala

@@ -17,6 +17,7 @@
 
 package kafka.utils
 
+import kafka.controller.LeaderIsrAndControllerEpoch
 import kafka.server.{ReplicaFetcherManager, KafkaConfig}
 import kafka.api.LeaderAndIsr
 import kafka.zk.ZooKeeperTestHarness
@@ -42,6 +43,8 @@ class ReplicationUtilsTest extends JUnit3Suite with ZooKeeperTestHarness {
   val topicDataMismatch = Json.encode(Map("controller_epoch" -> 1, "leader" -> 1,
     "versions" -> 2, "leader_epoch" -> 2,"isr" -> List(1,2)))
 
+  val topicDataLeaderIsrAndControllerEpoch = LeaderIsrAndControllerEpoch(LeaderAndIsr(1,leaderEpoch,List(1,2),0), controllerEpoch)
+
 
   override def setUp() {
     super.setUp()
@@ -92,4 +95,11 @@ class ReplicationUtilsTest extends JUnit3Suite with ZooKeeperTestHarness {
     assertEquals(newZkVersion3,-1)
   }
 
+  @Test
+  def testGetLeaderIsrAndEpochForPartition() {
+    val leaderIsrAndControllerEpoch = ReplicationUtils.getLeaderIsrAndEpochForPartition(zkClient, topic, partitionId)
+    assertEquals(topicDataLeaderIsrAndControllerEpoch, leaderIsrAndControllerEpoch.get)
+    assertEquals(None, ReplicationUtils.getLeaderIsrAndEpochForPartition(zkClient, topic, partitionId + 1))
+  }
+
 }