arrow-fx-coroutines / arrow.fx.coroutines / Atomic

Atomic

interface Atomic<A>

Creates a AtomicRef with a initial value of A.

Data type on top of atomic to use in parallel functions.

import arrow.fx.coroutines.*

suspend fun main() {
  val count = Atomic(0)

  (0 until 20_000).parTraverse {
    count.update(Int::inc)
  }
  println(count.get())
}

AtomicRef also offers some other interesting operators such as modify, tryUpdate, access & lens.

Functions

access	Obtain a snapshot of the current value, and a setter for updating it.`abstract suspend fun access():` `Pair<A, suspend (A) ->` `Boolean>`
get	Obtains the current value. Since AtomicRef is always guaranteed to have a value, the returned action completes immediately after being bound.`abstract suspend fun get(): A`
getAndSet	Replaces the current value with a, returning the old value.`abstract suspend fun getAndSet(a: A): A`
getAndUpdate	Modifies the current value using the supplied update function and returns the old value.`abstract suspend fun getAndUpdate(f: (A) -> A): A`
lens	Creates a AtomicRef for B based on provided a get and set operation.`open fun <B> lens(get: (A) -> B, set: (A, B) -> A):` `Atomic<B>`
modify	Modify allows to inspect the state A of the AtomicRef, update it and extract a different state B.`abstract suspend fun <B> modify(f: (A) ->` `Pair<A, B>): B`
modifyGet	ModifyGet allows to inspect state A, update it and extract a different state B. In contrast to modify it a Pair of the updated state A and the extracted state B.`abstract suspend fun <B> modifyGet(f: (A) ->` `Pair<A, B>):` `Pair<A, B>`
set	Sets the current value to a. The returned action completes after the reference has been successfully set.`abstract suspend fun set(a: A):` `Unit`
setAndGet	Replaces the current value with a, returning the new value.`abstract suspend fun setAndGet(a: A): A`
tryModify	Like tryUpdate but allows the update function to return an output value of type B.`abstract suspend fun <B> tryModify(f: (A) ->` `Pair<A, B>): B?`
tryUpdate	Attempts to modify the current value once, in contrast to update which calls f until it succeeds.`abstract suspend fun tryUpdate(f: (A) -> A):` `Boolean`
update	Updates the current value using the supplied function f.`abstract suspend fun update(f: (A) -> A):` `Unit`
updateAndGet	Modifies the current value using the supplied update function and returns the new value.`abstract suspend fun updateAndGet(f: (A) -> A): A`

Companion Object Functions

invoke	Creates a AtomicRef with a initial value of A.`suspend operator fun <A> invoke(a: A):` `Atomic<A>`
unsafe	`fun <A> unsafe(a: A):` `Atomic<A>`

Inheritors

SignallingAtomic Pure holder of a single atomic value of type A that can be both read and updated. Composes Signal and Atomic together to make an signalling atomic value.class SignallingAtomic<A> : Atomic<A>, Signal<A>