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zio/zio/Ref

Ref

zio.Ref
See theRef companion object
abstract class Ref[A] extends Serializable

A Ref is a purely functional description of a mutable reference. The fundamental operations of a Ref are set and get. set sets the reference to a new value. get gets the current value of the reference.

By default, Ref is implemented in terms of compare and swap operations for maximum performance and does not support performing effects within update operations. If you need to perform effects within update operations you can create a Ref.Synchronized, a specialized type of Ref that supports performing effects within update operations at some cost to performance. In this case writes will semantically block other writers, while multiple readers can read simultaneously.

NOTE: While Ref provides the functional equivalent of a mutable reference, the value inside the Ref should normally be immutable since compare and swap operations are not safe for mutable values that do not support concurrent access. If you do need to use a mutable value Ref.Synchronized will guarantee that access to the value is properly synchronized.

Attributes

Companion
object
Graph
Supertypes
trait Serializable
class Object
trait Matchable
class Any
Known subtypes
class Synchronized[A]

Members list

Value members

Abstract methods

def get(implicit trace: Trace): UIO[A]

Reads the value from the Ref.

Reads the value from the Ref.

Attributes

def modify[B](f: A => (B, A))(implicit trace: Trace): UIO[B]

Atomically modifies the Ref with the specified function, which computes a return value for the modification. This is a more powerful version of update.

Atomically modifies the Ref with the specified function, which computes a return value for the modification. This is a more powerful version of update.

Attributes

def set(a: A)(implicit trace: Trace): UIO[Unit]

Writes a new value to the Ref, with a guarantee of immediate consistency (at some cost to performance).

Writes a new value to the Ref, with a guarantee of immediate consistency (at some cost to performance).

Attributes

def setAsync(a: A)(implicit trace: Trace): UIO[Unit]

Writes a new value to the Ref without providing a guarantee of immediate consistency.

Writes a new value to the Ref without providing a guarantee of immediate consistency.

Attributes

Concrete methods

def getAndSet(a: A)(implicit trace: Trace): UIO[A]

Atomically writes the specified value to the Ref, returning the value immediately before modification.

Atomically writes the specified value to the Ref, returning the value immediately before modification.

Attributes

def getAndUpdate(f: A => A)(implicit trace: Trace): UIO[A]

Atomically modifies the Ref with the specified function, returning the value immediately before modification.

Atomically modifies the Ref with the specified function, returning the value immediately before modification.

Attributes

def getAndUpdateSome(pf: PartialFunction[A, A])(implicit trace: Trace): UIO[A]

Atomically modifies the Ref with the specified partial function, returning the value immediately before modification. If the function is undefined on the current value it doesn't change it.

Atomically modifies the Ref with the specified partial function, returning the value immediately before modification. If the function is undefined on the current value it doesn't change it.

Attributes

def modifySome[B](default: B)(pf: PartialFunction[A, (B, A)])(implicit trace: Trace): UIO[B]

Atomically modifies the Ref with the specified partial function, which computes a return value for the modification if the function is defined on the current value otherwise it returns a default value. This is a more powerful version of updateSome.

Atomically modifies the Ref with the specified partial function, which computes a return value for the modification if the function is defined on the current value otherwise it returns a default value. This is a more powerful version of updateSome.

Attributes

def update(f: A => A)(implicit trace: Trace): UIO[Unit]

Atomically modifies the Ref with the specified function.

Atomically modifies the Ref with the specified function.

Attributes

def updateAndGet(f: A => A)(implicit trace: Trace): UIO[A]

Atomically modifies the Ref with the specified function and returns the updated value.

Atomically modifies the Ref with the specified function and returns the updated value.

Attributes

def updateSome(pf: PartialFunction[A, A])(implicit trace: Trace): UIO[Unit]

Atomically modifies the Ref with the specified partial function. If the function is undefined on the current value it doesn't change it.

Atomically modifies the Ref with the specified partial function. If the function is undefined on the current value it doesn't change it.

Attributes

def updateSomeAndGet(pf: PartialFunction[A, A])(implicit trace: Trace): UIO[A]

Atomically modifies the Ref with the specified partial function. If the function is undefined on the current value it returns the old value without changing it.

Atomically modifies the Ref with the specified partial function. If the function is undefined on the current value it returns the old value without changing it.

Attributes

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