From 852ff5c25c9eaaab4fde01b9a1c26b4778c47bcc Mon Sep 17 00:00:00 2001
From: Sean McDirmid <sean.mcdirmid@gmail.com>
Date: Wed, 7 Feb 2007 12:22:04 +0000
Subject: Adding wrappers around Java's reference classes.

---
 src/library/scala/ref/PhantomReference.scala |  5 +++++
 src/library/scala/ref/Reference.scala        | 11 +++++++++++
 src/library/scala/ref/ReferenceQueue.scala   | 14 ++++++++++++++
 src/library/scala/ref/ReferenceWrapper.scala | 14 ++++++++++++++
 src/library/scala/ref/SoftReference.scala    |  8 ++++++++
 src/library/scala/ref/WeakReference.scala    |  8 ++++++++
 6 files changed, 60 insertions(+)
 create mode 100644 src/library/scala/ref/PhantomReference.scala
 create mode 100644 src/library/scala/ref/Reference.scala
 create mode 100644 src/library/scala/ref/ReferenceQueue.scala
 create mode 100644 src/library/scala/ref/ReferenceWrapper.scala
 create mode 100644 src/library/scala/ref/SoftReference.scala
 create mode 100644 src/library/scala/ref/WeakReference.scala

diff --git a/src/library/scala/ref/PhantomReference.scala b/src/library/scala/ref/PhantomReference.scala
new file mode 100644
index 0000000000..06216df3eb
--- /dev/null
+++ b/src/library/scala/ref/PhantomReference.scala
@@ -0,0 +1,5 @@
+package scala.ref;
+
+class PhantomReference[+T <: AnyRef](value : T, queue : ReferenceQueue[T]) extends ReferenceWrapper[T] {
+  val underlying = new java.lang.ref.PhantomReference(value, queue.underlying);
+}
diff --git a/src/library/scala/ref/Reference.scala b/src/library/scala/ref/Reference.scala
new file mode 100644
index 0000000000..30ace06b31
--- /dev/null
+++ b/src/library/scala/ref/Reference.scala
@@ -0,0 +1,11 @@
+package scala.ref;
+
+trait Reference[+T <: AnyRef] extends Function0[T] {
+  def isValid : Boolean;
+  def apply() : T;
+  def get = if (!isValid) None else Some(apply());
+  override def toString = if (!isValid) "<deleted>" else apply().toString;
+  def clear : Unit;
+  def enqueue : Boolean;
+  def isEnqueued : Boolean;
+}
diff --git a/src/library/scala/ref/ReferenceQueue.scala b/src/library/scala/ref/ReferenceQueue.scala
new file mode 100644
index 0000000000..1ed4c20af3
--- /dev/null
+++ b/src/library/scala/ref/ReferenceQueue.scala
@@ -0,0 +1,14 @@
+package scala.ref;
+
+class ReferenceQueue[+T <: AnyRef] {
+  private[ref] val underlying = new java.lang.ref.ReferenceQueue;
+  override def toString = underlying.toString;
+  class Wrapper(val underlying : java.lang.ref.Reference) extends ReferenceWrapper[T];
+  def Wrapper(ref : java.lang.ref.Reference) = ref match {
+    case null => None;
+    case ref => new Wrapper(ref);
+  }
+  def poll = Wrapper(underlying.poll);
+  def remove = Wrapper(underlying.remove);
+  def remove(timeout : Long) = Wrapper(underlying.remove(timeout));
+}
diff --git a/src/library/scala/ref/ReferenceWrapper.scala b/src/library/scala/ref/ReferenceWrapper.scala
new file mode 100644
index 0000000000..95f0047efe
--- /dev/null
+++ b/src/library/scala/ref/ReferenceWrapper.scala
@@ -0,0 +1,14 @@
+package scala.ref;
+
+trait ReferenceWrapper[+T <: AnyRef] extends Reference[T] {
+  val underlying : java.lang.ref.Reference;
+  def isValid = underlying.get != null;
+  def apply() = {
+    val ret = underlying.get.asInstanceOf[T];
+    if (ret eq null) throw new NoSuchElementException;
+    ret;
+  }
+  def clear = underlying.clear;
+  def enqueue = underlying.enqueue;
+  def isEnqueued = underlying.isEnqueued;
+}
diff --git a/src/library/scala/ref/SoftReference.scala b/src/library/scala/ref/SoftReference.scala
new file mode 100644
index 0000000000..a19ae08f5d
--- /dev/null
+++ b/src/library/scala/ref/SoftReference.scala
@@ -0,0 +1,8 @@
+package scala.ref;
+
+class SoftReference[+T <: AnyRef](value : T, queue : ReferenceQueue[T]) extends ReferenceWrapper[T] {
+  def this(value : T) = this(value, null);
+  val underlying =
+    if (queue == null) new java.lang.ref.SoftReference(value);
+    else new java.lang.ref.SoftReference(value, queue.underlying);
+}
diff --git a/src/library/scala/ref/WeakReference.scala b/src/library/scala/ref/WeakReference.scala
new file mode 100644
index 0000000000..6a27bda409
--- /dev/null
+++ b/src/library/scala/ref/WeakReference.scala
@@ -0,0 +1,8 @@
+package scala.ref;
+
+class WeakReference[+T <: AnyRef](value : T, queue : ReferenceQueue[T]) extends ReferenceWrapper[T] {
+  def this(value : T) = this(value, null);
+  val underlying =
+    if (queue == null) new java.lang.ref.WeakReference(value);
+    else new java.lang.ref.WeakReference(value, queue.underlying);
+}
-- 
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