Use require() for simpler syntax.

Author: darabos

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

@@ -76,9 +76,7 @@ object Partitioner {
  * produce an unexpected or incorrect result.
  */
 class HashPartitioner(partitions: Int) extends Partitioner {
-  if (partitions < 1) {
-    throw new IllegalArgumentException(s"Number of partitions ($partitions) must be positive.")
-  }
+  require(partitions > 0, s"Number of partitions ($partitions) must be positive.")
 
   def numPartitions: Int = partitions
 

core/src/main/scala/org/apache/spark/rdd/CoalescedRDD.scala

@@ -78,9 +78,7 @@ private[spark] class CoalescedRDD[T: ClassTag](
     balanceSlack: Double = 0.10)
   extends RDD[T](prev.context, Nil) {  // Nil since we implement getDependencies
 
-  if (maxPartitions < 1) {
-    throw new IllegalArgumentException(s"Number of partitions ($maxPartitions) must be positive.")
-  }
+  require(maxPartitions > 0, s"Number of partitions ($maxPartitions) must be positive.")
 
   override def getPartitions: Array[Partition] = {
     val pc = new PartitionCoalescer(maxPartitions, prev, balanceSlack)