From 8cf7228f8c1e11d67f4b7053b4ff2772e2bd79fc Mon Sep 17 00:00:00 2001 From: Paul Phillips Date: Sat, 20 Jun 2009 16:55:48 +0000 Subject: Created DelayedLazyVal for your def/val hybrid ... Created DelayedLazyVal for your def/val hybrid needs. --- src/library/scala/concurrent/DelayedLazyVal.scala | 44 +++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 src/library/scala/concurrent/DelayedLazyVal.scala (limited to 'src/library') diff --git a/src/library/scala/concurrent/DelayedLazyVal.scala b/src/library/scala/concurrent/DelayedLazyVal.scala new file mode 100644 index 0000000000..0fa3c1660b --- /dev/null +++ b/src/library/scala/concurrent/DelayedLazyVal.scala @@ -0,0 +1,44 @@ +/* __ *\ +** ________ ___ / / ___ Scala API ** +** / __/ __// _ | / / / _ | (c) 2003-2009, LAMP/EPFL ** +** __\ \/ /__/ __ |/ /__/ __ | ** +** /____/\___/_/ |_/____/_/ | | ** +** |/ ** +\* */ + +// $Id$ + +package scala.concurrent + +import annotation.experimental + +/** A DelayedLazyVal is a wrapper for lengthy + * computations which have a valid partially computed result. + * The first argument is a function for obtaining the result + * at any given point in time, and the second is the lengthy + * computation. Once the computation is complete, the apply() + * method will stop recalculating it and return a fixed value + * from that point forward. + * + * @param f the function to obtain the current value at any point in time + * @param body the computation to run to completion in another thread + * + * @author Paul Phillips + * @version 2.8 + */ +@experimental +class DelayedLazyVal[T](f: () => T, body: => Unit) { + @volatile private[this] var isDone = false + private[this] lazy val complete = f() + + /** The current result of f(), or the final result if complete. + * + * @return the current value + */ + def apply(): T = if (isDone) complete else f() + + ops.future { + body + isDone = true + } +} \ No newline at end of file -- cgit v1.2.3