aboutsummaryrefslogtreecommitdiffstats
path: root/infrastructure/net.appjet.oui/dynamicvar.scala
diff options
context:
space:
mode:
Diffstat (limited to 'infrastructure/net.appjet.oui/dynamicvar.scala')
-rw-r--r--infrastructure/net.appjet.oui/dynamicvar.scala49
1 files changed, 49 insertions, 0 deletions
diff --git a/infrastructure/net.appjet.oui/dynamicvar.scala b/infrastructure/net.appjet.oui/dynamicvar.scala
new file mode 100644
index 0000000..b1f8c2e
--- /dev/null
+++ b/infrastructure/net.appjet.oui/dynamicvar.scala
@@ -0,0 +1,49 @@
+/**
+ * Copyright 2009 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.appjet.oui;
+
+class NoninheritedDynamicVariable[T](init: T) {
+ private val tl = new ThreadLocal[T] {
+ override def initialValue = init.asInstanceOf[T with AnyRef]
+ }
+
+ /** Retrieve the current value */
+ def value: T = tl.get.asInstanceOf[T]
+
+
+ /** Set the value of the variable while executing the specified
+ * thunk.
+ *
+ * @param newval The value to which to set the fluid
+ * @param thunk The code to evaluate under the new setting
+ */
+ def withValue[S](newval: T)(thunk: =>S): S = {
+ val oldval = value
+ tl.set(newval)
+
+ try { thunk } finally {
+ tl.set(oldval)
+ }
+ }
+
+ /** Change the currently bound value, discarding the old value.
+ * Usually <code>withValue()</code> gives better semantics.
+ */
+ def value_=(newval: T) = { tl.set(newval) }
+
+ override def toString: String = "NoninheritedDynamicVariable(" + value +")"
+}