SPARK-6993 : Add default min, max methods for JavaDoubleRDD

The default method will use Guava's Ordering instead of
java.util.Comparator.naturalOrder() because it's not available
in Java 7, only in Java 8.

Author: Olivier Girardot <o.girardot@lateral-thoughts.com>

Closes #5571 from ogirardot/master and squashes the following commits:

7fe2e9e [Olivier Girardot] SPARK-6993 : Add default min, max methods for JavaDoubleRDD

2 files changed, 28 insertions, 0 deletions

diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala b/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala
index 79e4ebf2db..61af867b11 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaDoubleRDD.scala
@@ -164,6 +164,20 @@ class JavaDoubleRDD(val srdd: RDD[scala.Double])
   def sum(): JDouble = srdd.sum()
 
   /**
+   * Returns the minimum element from this RDD as defined by
+   * the default comparator natural order.
+   * @return the minimum of the RDD
+   */
+  def min(): JDouble = min(com.google.common.collect.Ordering.natural())
+
+  /**
+   * Returns the maximum element from this RDD as defined by
+   * the default comparator natural order.
+   * @return the maximum of the RDD
+   */
+  def max(): JDouble = max(com.google.common.collect.Ordering.natural())
+
+  /**
    * Return a [[org.apache.spark.util.StatCounter]] object that captures the mean, variance and
    * count of the RDD's elements in one operation.
    */
diff --git a/core/src/test/java/org/apache/spark/JavaAPISuite.java b/core/src/test/java/org/apache/spark/JavaAPISuite.java
index d4b5bb5191..8a4f2a08fe 100644
--- a/core/src/test/java/org/apache/spark/JavaAPISuite.java
+++ b/core/src/test/java/org/apache/spark/JavaAPISuite.java
@@ -762,6 +762,20 @@ public class JavaAPISuite implements Serializable {
   }
 
   @Test
+  public void naturalMax() {
+    JavaDoubleRDD rdd = sc.parallelizeDoubles(Arrays.asList(1.0, 2.0, 3.0, 4.0));
+    double max = rdd.max();
+    Assert.assertTrue(4.0 == max);
+  }
+
+  @Test
+  public void naturalMin() {
+    JavaDoubleRDD rdd = sc.parallelizeDoubles(Arrays.asList(1.0, 2.0, 3.0, 4.0));
+    double max = rdd.min();
+    Assert.assertTrue(1.0 == max);
+  }
+
+  @Test
   public void takeOrdered() {
     JavaDoubleRDD rdd = sc.parallelizeDoubles(Arrays.asList(1.0, 2.0, 3.0, 4.0));
     Assert.assertEquals(Arrays.asList(1.0, 2.0), rdd.takeOrdered(2, new DoubleComparator()));