SPARK-2740: allow user to specify ascending and numPartitions for sortBy...

It should be more convenient if user can specify ascending and numPartitions when calling sortByKey.

Author: Rui Li <rui.li@intel.com>

Closes #1645 from lirui-intel/spark-2740 and squashes the following commits:

fb5d52e [Rui Li] SPARK-2740: allow user to specify ascending and numPartitions for sortByKey

1 files changed, 11 insertions, 0 deletions

diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala b/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala
index 47708cb2e7..76d4193e96 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaPairRDD.scala
@@ -789,6 +789,17 @@ class JavaPairRDD[K, V](val rdd: RDD[(K, V)])
    * (in the `save` case, they will be written to multiple `part-X` files in the filesystem, in
    * order of the keys).
    */
+  def sortByKey(ascending: Boolean, numPartitions: Int): JavaPairRDD[K, V] = {
+    val comp = com.google.common.collect.Ordering.natural().asInstanceOf[Comparator[K]]
+    sortByKey(comp, ascending, numPartitions)
+  }
+
+  /**
+   * Sort the RDD by key, so that each partition contains a sorted range of the elements. Calling
+   * `collect` or `save` on the resulting RDD will return or output an ordered list of records
+   * (in the `save` case, they will be written to multiple `part-X` files in the filesystem, in
+   * order of the keys).
+   */
   def sortByKey(comp: Comparator[K]): JavaPairRDD[K, V] = sortByKey(comp, true)
 
   /**