[SPARK-4819] Remove Guava's "Optional" from public API

Replace Guava `Optional` with (an API clone of) Java 8 `java.util.Optional` (edit: and a clone of Guava `Optional`)

See also https://github.com/apache/spark/pull/10512

Author: Sean Owen <sowen@cloudera.com>

Closes #10513 from srowen/SPARK-4819.

4 files changed, 4 insertions, 12 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 59af1052eb..fb04472ee7 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
@@ -25,7 +25,6 @@ import scala.collection.JavaConverters._
 import scala.language.implicitConversions
 import scala.reflect.ClassTag
 
-import com.google.common.base.Optional
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.io.compress.CompressionCodec
 import org.apache.hadoop.mapred.{JobConf, OutputFormat}
@@ -655,7 +654,6 @@ class JavaPairRDD[K, V](val rdd: RDD[(K, V)])
    * keys; this also retains the original RDD's partitioning.
    */
   def flatMapValues[U](f: JFunction[V, java.lang.Iterable[U]]): JavaPairRDD[K, U] = {
-    import scala.collection.JavaConverters._
     def fn: (V) => Iterable[U] = (x: V) => f.call(x).asScala
     implicit val ctag: ClassTag[U] = fakeClassTag
     fromRDD(rdd.flatMapValues(fn))
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala b/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala
index 242438237f..0f8d13cf5c 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaRDDLike.scala
@@ -24,7 +24,6 @@ import java.util.{Comparator, Iterator => JIterator, List => JList}
 import scala.collection.JavaConverters._
 import scala.reflect.ClassTag
 
-import com.google.common.base.Optional
 import org.apache.hadoop.io.compress.CompressionCodec
 
 import org.apache.spark._
@@ -122,7 +121,6 @@ trait JavaRDDLike[T, This <: JavaRDDLike[T, This]] extends Serializable {
    *  RDD, and then flattening the results.
    */
   def flatMap[U](f: FlatMapFunction[T, U]): JavaRDD[U] = {
-    import scala.collection.JavaConverters._
     def fn: (T) => Iterable[U] = (x: T) => f.call(x).asScala
     JavaRDD.fromRDD(rdd.flatMap(fn)(fakeClassTag[U]))(fakeClassTag[U])
   }
@@ -132,7 +130,6 @@ trait JavaRDDLike[T, This <: JavaRDDLike[T, This]] extends Serializable {
    *  RDD, and then flattening the results.
    */
   def flatMapToDouble(f: DoubleFlatMapFunction[T]): JavaDoubleRDD = {
-    import scala.collection.JavaConverters._
     def fn: (T) => Iterable[jl.Double] = (x: T) => f.call(x).asScala
     new JavaDoubleRDD(rdd.flatMap(fn).map((x: jl.Double) => x.doubleValue()))
   }
@@ -142,7 +139,6 @@ trait JavaRDDLike[T, This <: JavaRDDLike[T, This]] extends Serializable {
    *  RDD, and then flattening the results.
    */
   def flatMapToPair[K2, V2](f: PairFlatMapFunction[T, K2, V2]): JavaPairRDD[K2, V2] = {
-    import scala.collection.JavaConverters._
     def fn: (T) => Iterable[(K2, V2)] = (x: T) => f.call(x).asScala
     def cm: ClassTag[(K2, V2)] = implicitly[ClassTag[(K2, V2)]]
     JavaPairRDD.fromRDD(rdd.flatMap(fn)(cm))(fakeClassTag[K2], fakeClassTag[V2])
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala b/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala
index 9990b22e14..01433ca2ef 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala
@@ -25,7 +25,6 @@ import scala.collection.JavaConverters._
 import scala.language.implicitConversions
 import scala.reflect.ClassTag
 
-import com.google.common.base.Optional
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.mapred.{InputFormat, JobConf}
 import org.apache.hadoop.mapreduce.{InputFormat => NewInputFormat}
diff --git a/core/src/main/scala/org/apache/spark/api/java/JavaUtils.scala b/core/src/main/scala/org/apache/spark/api/java/JavaUtils.scala
index b2a4d053fa..f820401da2 100644
--- a/core/src/main/scala/org/apache/spark/api/java/JavaUtils.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaUtils.scala
@@ -22,13 +22,12 @@ import java.util.Map.Entry
 
 import scala.collection.mutable
 
-import com.google.common.base.Optional
-
 private[spark] object JavaUtils {
   def optionToOptional[T](option: Option[T]): Optional[T] =
-    option match {
-      case Some(value) => Optional.of(value)
-      case None => Optional.absent()
+    if (option.isDefined) {
+      Optional.of(option.get)
+    } else {
+      Optional.empty[T]
     }
 
   // Workaround for SPARK-3926 / SI-8911