SPARK-1801. expose InterruptibleIterator and TaskKilledException in d…

…eve...

...loper api

Author: Koert Kuipers <koert@tresata.com>

Closes apache#764 from koertkuipers/feat-rdd-developerapi and squashes the following commits:

8516dd2 [Koert Kuipers] SPARK-1801. expose InterruptibleIterator and TaskKilledException in developer api

core/src/main/scala/org/apache/spark/InterruptibleIterator.scala

@@ -17,11 +17,15 @@
 
 package org.apache.spark
 
+import org.apache.spark.annotation.DeveloperApi
+
 /**
+ * :: DeveloperApi ::
  * An iterator that wraps around an existing iterator to provide task killing functionality.
  * It works by checking the interrupted flag in [[TaskContext]].
  */
-private[spark] class InterruptibleIterator[+T](val context: TaskContext, val delegate: Iterator[T])
+@DeveloperApi
+class InterruptibleIterator[+T](val context: TaskContext, val delegate: Iterator[T])
   extends Iterator[T] {
 
   def hasNext: Boolean = {

core/src/main/scala/org/apache/spark/TaskKilledException.scala

@@ -17,7 +17,11 @@
 
 package org.apache.spark
 
+import org.apache.spark.annotation.DeveloperApi
+
 /**
- * Exception for a task getting killed.
+ * :: DeveloperApi ::
+ * Exception thrown when a task is explicitly killed (i.e., task failure is expected).
  */
-private[spark] class TaskKilledException extends RuntimeException
+@DeveloperApi
+class TaskKilledException extends RuntimeException