Made RedBlack private to the scala.collection.immutable package.

Use ArrayStack instead of Stack in TreeIterator for slightly increased
performance.

2 files changed, 12 insertions, 10 deletions

diff --git a/src/library/scala/collection/immutable/RedBlack.scala b/src/library/scala/collection/immutable/RedBlack.scala
index 4b81182657..19e0e5ae55 100644
--- a/src/library/scala/collection/immutable/RedBlack.scala
+++ b/src/library/scala/collection/immutable/RedBlack.scala
@@ -15,7 +15,8 @@ package immutable
  *
  *  @since 2.3
  */
-object RedBlack extends Serializable {
+private[immutable]
+object RedBlack {
 
   private def blacken[A, B](t: Tree[A, B]): Tree[A, B] = t match {
     case RedTree(k, v, l, r) => BlackTree(k, v, l, r)
@@ -302,8 +303,6 @@ object RedBlack extends Serializable {
   }
 
   private[this] class TreeIterator[A, B](tree: NonEmpty[A, B]) extends Iterator[(A, B)] {
-    import collection.mutable.Stack
-
     override def hasNext: Boolean = !next.isEmpty
 
     override def next: (A, B) = next match {
@@ -326,7 +325,7 @@ object RedBlack extends Serializable {
       }
     }
 
-    private[this] val path: Stack[NonEmpty[A, B]] = Stack.empty[NonEmpty[A, B]]
+    private[this] val path = mutable.ArrayStack.empty[NonEmpty[A, B]]
     addLeftMostBranchToPath(tree)
     private[this] var next: Tree[A, B] = path.pop()
   }
diff --git a/test/files/scalacheck/redblack.scala b/test/files/scalacheck/redblack.scala
index 011a5d0ca5..78fb645ce8 100644
--- a/test/files/scalacheck/redblack.scala
+++ b/test/files/scalacheck/redblack.scala
@@ -1,3 +1,4 @@
+import collection.immutable._
 import org.scalacheck._
 import Prop._
 import Gen._
@@ -14,11 +15,12 @@ Both children of every red node are black.
 Every simple path from a given node to any of its descendant leaves contains the same number of black nodes.
 */
 
+package scala.collection.immutable {
 abstract class RedBlackTest extends Properties("RedBlack") {
   def minimumSize = 0
   def maximumSize = 5
 
-  import collection.immutable.RedBlack._
+  import RedBlack._
   
   def nodeAt[A](tree: Tree[String, A], n: Int): Option[(String, A)] = if (n < tree.iterator.size && n >= 0)
     Some(tree.iterator.drop(n).next)
@@ -64,7 +66,7 @@ abstract class RedBlackTest extends Properties("RedBlack") {
 trait RedBlackInvariants {
   self: RedBlackTest =>
   
-  import collection.immutable.RedBlack._
+  import RedBlack._
     
   def rootIsBlack[A](t: Tree[String, A]) = t.isBlack
   
@@ -110,7 +112,7 @@ trait RedBlackInvariants {
 }
 
 object TestInsert extends RedBlackTest with RedBlackInvariants {
-  import collection.immutable.RedBlack._
+  import RedBlack._
   
   override type ModifyParm = Int
   override def genParm(tree: Tree[String, Int]): Gen[ModifyParm] = choose(0, tree.iterator.size + 1)
@@ -130,7 +132,7 @@ object TestInsert extends RedBlackTest with RedBlackInvariants {
 }
 
 object TestModify extends RedBlackTest {
-  import collection.immutable.RedBlack._
+  import RedBlack._
   
   def newValue = 1
   override def minimumSize = 1
@@ -148,7 +150,7 @@ object TestModify extends RedBlackTest {
 }
 
 object TestDelete extends RedBlackTest with RedBlackInvariants  {
-  import collection.immutable.RedBlack._
+  import RedBlack._
 
   override def minimumSize = 1
   override type ModifyParm = Int
@@ -165,7 +167,7 @@ object TestDelete extends RedBlackTest with RedBlackInvariants  {
 }
 
 object TestRange extends RedBlackTest with RedBlackInvariants  {
-  import collection.immutable.RedBlack._
+  import RedBlack._
   
   override type ModifyParm = (Option[Int], Option[Int])
   override def genParm(tree: Tree[String, Int]): Gen[ModifyParm] = for {
@@ -199,6 +201,7 @@ object TestRange extends RedBlackTest with RedBlackInvariants  {
     filteredTree == newTree.iterator.map(_._1).toList
   }
 }
+}
 
 object Test extends Properties("RedBlack") {
   include(TestInsert)