diff options
Diffstat (limited to 'src/library/scala/collection/immutable/Set.scala')
| -rw-r--r-- | src/library/scala/collection/immutable/Set.scala | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/src/library/scala/collection/immutable/Set.scala b/src/library/scala/collection/immutable/Set.scala index be1e86bcdd..1bec1b9a48 100644 --- a/src/library/scala/collection/immutable/Set.scala +++ b/src/library/scala/collection/immutable/Set.scala @@ -41,12 +41,22 @@ trait Set[A] extends Iterable[A] object Set extends SetFactory[Set] { implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, Set[A]] = setCanBuildFrom[A] - override def empty[A]: Set[A] = new EmptySet[A] + override def empty[A]: Set[A] = EmptySet.asInstanceOf[Set[A]] private val hashSeed = "Set".hashCode /** An optimized representation for immutable empty sets */ @serializable + private object EmptySet extends Set[Any] { + override def size: Int = 0 + def contains(elem: Any): Boolean = false + def + (elem: Any): Set[Any] = new Set1(elem) + def - (elem: Any): Set[Any] = this + def iterator: Iterator[Any] = Iterator.empty + override def foreach[U](f: Any => U): Unit = {} + } + + @serializable @deprecated("use `Set.empty' instead") class EmptySet[A] extends Set[A] { override def size: Int = 0 def contains(elem: A): Boolean = false @@ -66,7 +76,7 @@ object Set extends SetFactory[Set] { if (contains(elem)) this else new Set2(elem1, elem) def - (elem: A): Set[A] = - if (elem == elem1) new EmptySet[A] + if (elem == elem1) Set.empty else this def iterator: Iterator[A] = Iterator(elem1) |