scala.concurrent.DelayedLazyVal.scala Maven / Gradle / Ivy
/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala.concurrent
/** 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
*/
@deprecated("`DelayedLazyVal` Will be removed in the future.", since = "2.13.0")
class DelayedLazyVal[T](f: () => T, body: => Unit)(implicit exec: ExecutionContext){
@volatile private[this] var _isDone = false
private[this] lazy val complete = f()
/** Whether the computation is complete.
*
* @return true if the computation is complete.
*/
def isDone: Boolean = _isDone
/** The current result of f(), or the final result if complete.
*
* @return the current value
*/
def apply(): T = if (isDone) complete else f()
exec.execute(() => {
body; _isDone = true
})
}