Scala example source code file (Deadline.scala)

This example Scala source code file (Deadline.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

boolean, concurrent, deadline, deadlineisordered, duration, finiteduration, nanoseconds, ordered, ordering, time

The Deadline.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

package scala.concurrent.duration

/**
 * This class stores a deadline, as obtained via `Deadline.now` or the
 * duration DSL:
 *
 * {{{
 * import scala.concurrent.duration._
 * 3.seconds.fromNow
 * }}}
 *
 * Its main purpose is to manage repeated attempts to achieve something (like
 * awaiting a condition) by offering the methods `hasTimeLeft` and `timeLeft`.  All
 * durations are measured according to `System.nanoTime` aka wall-time; this
 * does not take into account changes to the system clock (such as leap
 * seconds).
 */
case class Deadline private (time: FiniteDuration) extends Ordered[Deadline] {
  /**
   * Return a deadline advanced (i.e. moved into the future) by the given duration.
   */
  def +(other: FiniteDuration): Deadline = copy(time = time + other)
  /**
   * Return a deadline moved backwards (i.e. towards the past) by the given duration.
   */
  def -(other: FiniteDuration): Deadline = copy(time = time - other)
  /**
   * Calculate time difference between this and the other deadline, where the result is directed (i.e. may be negative).
   */
  def -(other: Deadline): FiniteDuration = time - other.time
  /**
   * Calculate time difference between this duration and now; the result is negative if the deadline has passed.
   *
   * '''''Note that on some systems this operation is costly because it entails a system call.'''''
   * Check `System.nanoTime` for your platform.
   */
  def timeLeft: FiniteDuration = this - Deadline.now
  /**
   * Determine whether the deadline still lies in the future at the point where this method is called.
   *
   * '''''Note that on some systems this operation is costly because it entails a system call.'''''
   * Check `System.nanoTime` for your platform.
   */
  def hasTimeLeft(): Boolean = !isOverdue()
  /**
   * Determine whether the deadline lies in the past at the point where this method is called.
   *
   * '''''Note that on some systems this operation is costly because it entails a system call.'''''
   * Check `System.nanoTime` for your platform.
   */
  def isOverdue(): Boolean = (time.toNanos - System.nanoTime()) < 0
  /**
   * The natural ordering for deadline is determined by the natural order of the underlying (finite) duration.
   */
  def compare(other: Deadline) = time compare other.time
}

object Deadline {
  /**
   * Construct a deadline due exactly at the point where this method is called. Useful for then
   * advancing it to obtain a future deadline, or for sampling the current time exactly once and
   * then comparing it to multiple deadlines (using subtraction).
   */
  def now: Deadline = Deadline(Duration(System.nanoTime, NANOSECONDS))

  /**
   * The natural ordering for deadline is determined by the natural order of the underlying (finite) duration.
   */
  implicit object DeadlineIsOrdered extends Ordering[Deadline] {
    def compare(a: Deadline, b: Deadline) = a compare b
  }

}