diff options
| -rw-r--r-- | src/library/scala/Enumeration.scala | 41 |
1 files changed, 35 insertions, 6 deletions
diff --git a/src/library/scala/Enumeration.scala b/src/library/scala/Enumeration.scala index 8a708a4615..205cf1cf84 100644 --- a/src/library/scala/Enumeration.scala +++ b/src/library/scala/Enumeration.scala @@ -16,6 +16,15 @@ import scala.collection.mutable.{Builder, AddingBuilder, Map, HashMap} import scala.collection.immutable.{Set, BitSet} import scala.collection.generic.CanBuildFrom +private object Enumeration { + + /* This map is used to cache enumeration instances for + resolving enumeration _values_ to equal objects (by-reference) + when values are deserialized. */ + private val emap: Map[Class[_], Enumeration] = new HashMap + +} + /** <p> * Defines a finite set of values specific to the enumeration. Typically * these values enumerate all possible forms something can take and provide a @@ -61,6 +70,21 @@ abstract class Enumeration(initial: Int, names: String*) { def this() = this(0, null) def this(names: String*) = this(0, names: _*) + Enumeration.emap.get(getClass) match { + case None => + Enumeration.emap += (getClass -> this) + case Some(_) => + /* do nothing */ + } + + private def readResolve(): AnyRef = Enumeration.emap.get(getClass) match { + case None => + Enumeration.emap += (getClass -> this) + this + case Some(existing) => + existing + } + /** The name of this enumeration. */ override def toString = { @@ -192,13 +216,13 @@ abstract class Enumeration(initial: Int, names: String*) { /** The type of the enumerated values. */ @serializable @SerialVersionUID(7091335633555234129L) - abstract class Value extends Ordered[Enumeration#Value] { + abstract class Value extends Ordered[Value] { /** the id and bit location of this enumeration value */ def id: Int - override def compare(that: Enumeration#Value): Int = this.id - that.id + override def compare(that: Value): Int = this.id - that.id override def equals(other: Any): Boolean = other match { - case that: Enumeration#Value => compare(that) == 0 + case that: Value => compare(that) == 0 case _ => false } override def hashCode: Int = id.hashCode @@ -211,7 +235,7 @@ abstract class Enumeration(initial: Int, names: String*) { if (id >= 32) throw new IllegalArgumentException 1 << id } - /** this enumeration value as an <code>Long</code> bit mask. + /** this enumeration value as a <code>Long</code> bit mask. * @throws IllegalArgumentException if <code>id</code> is greater than 63 */ @deprecated("mask64 will be removed") @@ -243,9 +267,14 @@ abstract class Enumeration(initial: Int, names: String*) { override def toString() = if (name eq null) Enumeration.this.nameOf(i) else name - private def readResolve(): AnyRef = - if (vmap ne null) vmap(i) + private def readResolve(): AnyRef = { + val enum = Enumeration.emap.get(Enumeration.this.getClass) match { + case None => Enumeration.this + case Some(existing) => existing + } + if (enum.vmap ne null) enum.vmap(i) else this + } } /** A class for sets of values |