[SPARK-6429] Implement hashCode and equals together

## What changes were proposed in this pull request?

Implement some `hashCode` and `equals` together in order to enable the scalastyle.
This is a first batch, I will continue to implement them but I wanted to know your thoughts.

Author: Joan <joan@goyeau.com>

Closes #12157 from joan38/SPARK-6429-HashCode-Equals.

6 files changed, 21 insertions, 12 deletions

diff --git a/core/src/main/scala/org/apache/spark/Partition.scala b/core/src/main/scala/org/apache/spark/Partition.scala
index dd3f28e419..e10660793d 100644
--- a/core/src/main/scala/org/apache/spark/Partition.scala
+++ b/core/src/main/scala/org/apache/spark/Partition.scala
@@ -28,4 +28,6 @@ trait Partition extends Serializable {
 
   // A better default implementation of HashCode
   override def hashCode(): Int = index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }
diff --git a/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala b/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala
index 7bc1eb0436..2381f54ee3 100644
--- a/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/CoGroupedRDD.scala
@@ -58,10 +58,10 @@ private[spark] case class NarrowCoGroupSplitDep(
  *                   narrowDeps should always be equal to the number of parents.
  */
 private[spark] class CoGroupPartition(
-    idx: Int, val narrowDeps: Array[Option[NarrowCoGroupSplitDep]])
+    override val index: Int, val narrowDeps: Array[Option[NarrowCoGroupSplitDep]])
   extends Partition with Serializable {
-  override val index: Int = idx
-  override def hashCode(): Int = idx
+  override def hashCode(): Int = index
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
index 6b1e15572c..b22134af45 100644
--- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala
@@ -53,14 +53,14 @@ import org.apache.spark.util.{NextIterator, SerializableConfiguration, ShutdownH
 /**
  * A Spark split class that wraps around a Hadoop InputSplit.
  */
-private[spark] class HadoopPartition(rddId: Int, idx: Int, s: InputSplit)
+private[spark] class HadoopPartition(rddId: Int, override val index: Int, s: InputSplit)
   extends Partition {
 
   val inputSplit = new SerializableWritable[InputSplit](s)
 
-  override def hashCode(): Int = 41 * (41 + rddId) + idx
+  override def hashCode(): Int = 31 * (31 + rddId) + index
 
-  override val index: Int = idx
+  override def equals(other: Any): Boolean = super.equals(other)
 
   /**
    * Get any environment variables that should be added to the users environment when running pipes
diff --git a/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
index a71c191b31..ad7c2216a0 100644
--- a/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala
@@ -45,7 +45,10 @@ private[spark] class NewHadoopPartition(
   extends Partition {
 
   val serializableHadoopSplit = new SerializableWritable(rawSplit)
-  override def hashCode(): Int = 41 * (41 + rddId) + index
+
+  override def hashCode(): Int = 31 * (31 + rddId) + index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**
diff --git a/core/src/main/scala/org/apache/spark/rdd/PartitionerAwareUnionRDD.scala b/core/src/main/scala/org/apache/spark/rdd/PartitionerAwareUnionRDD.scala
index 0abba15bec..b6366f3e68 100644
--- a/core/src/main/scala/org/apache/spark/rdd/PartitionerAwareUnionRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/PartitionerAwareUnionRDD.scala
@@ -31,12 +31,13 @@ import org.apache.spark.util.Utils
 private[spark]
 class PartitionerAwareUnionRDDPartition(
     @transient val rdds: Seq[RDD[_]],
-    val idx: Int
+    override val index: Int
   ) extends Partition {
-  var parents = rdds.map(_.partitions(idx)).toArray
+  var parents = rdds.map(_.partitions(index)).toArray
 
-  override val index = idx
-  override def hashCode(): Int = idx
+  override def hashCode(): Int = index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 
   @throws(classOf[IOException])
   private def writeObject(oos: ObjectOutputStream): Unit = Utils.tryOrIOException {
diff --git a/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala b/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala
index 800b42505d..29d5d74650 100644
--- a/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/ShuffledRDD.scala
@@ -25,7 +25,10 @@ import org.apache.spark.serializer.Serializer
 
 private[spark] class ShuffledRDDPartition(val idx: Int) extends Partition {
   override val index: Int = idx
-  override def hashCode(): Int = idx
+
+  override def hashCode(): Int = index
+
+  override def equals(other: Any): Boolean = super.equals(other)
 }
 
 /**