akka.util.OptionVal.scala Maven / Gradle / Ivy
/*
* Copyright (C) 2016-2019 Lightbend Inc.
*/
package akka.util
/**
* INTERNAL API
*/
private[akka] object OptionVal {
def apply[A](x: A): OptionVal[A] = new OptionVal(x)
object Some {
def apply[A](x: A): OptionVal[A] = new OptionVal(x)
def unapply[A](x: OptionVal[A]): OptionVal[A] = x
}
def none[A]: OptionVal[A] = None.asInstanceOf[OptionVal[A]]
/**
* Represents non-existent values, `null` values.
*/
val None = new OptionVal[Null](null)
}
/**
* INTERNAL API
* Represents optional values similar to `scala.Option`, but
* as a value class to avoid allocations.
*
* Note that it can be used in pattern matching without allocations
* because it has name based extractor using methods `isEmpty` and `get`.
* See https://hseeberger.wordpress.com/2013/10/04/name-based-extractors-in-scala-2-11/
*/
private[akka] final class OptionVal[+A](val x: A) extends AnyVal {
/**
* Returns true if the option is `OptionVal.None`, false otherwise.
*/
def isEmpty: Boolean =
x == null
/**
* Returns true if the option is `OptionVal.None`, false otherwise.
*/
def isDefined: Boolean = !isEmpty
/**
* Returns the option's value if the option is nonempty, otherwise
* return `default`.
*/
def getOrElse[B >: A](default: B): B =
if (x == null) default else x
/**
* Convert to `scala.Option`
*/
def toOption: Option[A] =
Option(x)
def contains[B >: A](it: B): Boolean =
x != null && x == it
/**
* Returns the option's value if it is nonempty, or `null` if it is empty.
*/
def orNull[A1 >: A](implicit ev: Null <:< A1): A1 = this.getOrElse(ev(null))
/**
* Returns the option's value.
* @note The option must be nonEmpty.
* @throws java.util.NoSuchElementException if the option is empty.
*/
def get: A =
if (x == null) throw new NoSuchElementException("OptionVal.None.get")
else x
override def toString: String =
if (x == null) "None" else s"Some($x)"
}
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