package atomic
A small toolkit of classes that support compare-and-swap semantics for safe mutation of variables.
On top of the JVM, this means dealing with lock-free thread-safe programming. Also works on top of Javascript, with Scala.js, for API compatibility purposes and because it's a useful way to box a value.
The backbone of Atomic references is this method:
def compareAndSet(expect: T, update: T): Boolean
This method atomically sets a variable to the update
value if it
currently holds the expect
value, reporting true
on success or
false
on failure. The classes in this package also contain
methods to get and unconditionally set values.
Building a reference is easy with the provided constructor, which
will automatically return the most specific type needed (in the
following sample, that's an AtomicDouble
, inheriting from
AtomicNumber[A]
):
val atomicNumber = Atomic(12.2) atomicNumber.incrementAndGet() // => 13.2
These also provide useful helpers for atomically mutating of
values (i.e. transform
, transformAndGet
, getAndTransform
,
etc...) or of numbers of any kind (incrementAndGet
, getAndAdd
,
etc...).
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- package.scala
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Type Members
- abstract class Atomic[A] extends Serializable
Base trait of all atomic references, no matter the type.
- final class AtomicAny[A <: AnyRef] extends Atomic[A]
Atomic references wrapping
AnyRef
values.Atomic references wrapping
AnyRef
values.- A
is forced to be an
AnyRef
because the equality test is by reference and not by value.
- final class AtomicBoolean extends Atomic[Boolean]
Atomic references wrapping
Boolean
values.Atomic references wrapping
Boolean
values.Note that the equality test in
compareAndSet
is value based, sinceBoolean
is a primitive. - trait AtomicBuilder[A, R <: Atomic[A]] extends Serializable
For a given
A
indicates the most specificAtomic[A]
reference type to use.For a given
A
indicates the most specificAtomic[A]
reference type to use.In essence this is implementing a form of specialization driven by implicits.
- final class AtomicByte extends AtomicNumber[Byte]
Atomic references wrapping
Byte
values.Atomic references wrapping
Byte
values.Note that the equality test in
compareAndSet
is value based, sinceByte
is a primitive. - final class AtomicChar extends AtomicNumber[Char]
Atomic references wrapping
Char
values.Atomic references wrapping
Char
values.Note that the equality test in
compareAndSet
is value based, sinceChar
is a primitive. - final class AtomicDouble extends AtomicNumber[Double]
Atomic references wrapping
Double
values.Atomic references wrapping
Double
values.Note that the equality test in
compareAndSet
is value based, sinceDouble
is a primitive. - final class AtomicFloat extends AtomicNumber[Float]
Atomic references wrapping
Float
values.Atomic references wrapping
Float
values.Note that the equality test in
compareAndSet
is value based, sinceFloat
is a primitive. - final class AtomicInt extends AtomicNumber[Int]
Atomic references wrapping
Int
values.Atomic references wrapping
Int
values.Note that the equality test in
compareAndSet
is value based, sinceInt
is a primitive. - final class AtomicLong extends AtomicNumber[Long]
Atomic references wrapping
Long
values.Atomic references wrapping
Long
values.Note that the equality test in
compareAndSet
is value based, sinceLong
is a primitive. - abstract class AtomicNumber[A] extends Atomic[A]
Represents an Atomic reference holding a number, providing helpers for easily incrementing and decrementing it.
Represents an Atomic reference holding a number, providing helpers for easily incrementing and decrementing it.
- A
should be something that's Numeric
- final class AtomicNumberAny[A <: AnyRef] extends AtomicNumber[A]
Atomic references wrapping any values implementing Scala's
Numeric
type class.Atomic references wrapping any values implementing Scala's
Numeric
type class.Note that the equality test in
compareAndSet
is reference based. This is because we are storingAnyRef
references and on top of the JVM that's the semantic ofcompareAndSet
. This behavior is kept consistent even on top of Scala.js / Javascript. - final class AtomicShort extends AtomicNumber[Short]
Atomic references wrapping
Short
values.Atomic references wrapping
Short
values.Note that the equality test in
compareAndSet
is value based, sinceShort
is a primitive. - sealed abstract class PaddingStrategy extends AnyRef
For applying padding to atomic references, in order to reduce cache contention.
For applying padding to atomic references, in order to reduce cache contention. JEP 142 should reduce the need for this along with the
@Contended
annotation, however that might have security restrictions, the runtime might not act on it since it's just a recommendation, plus it's nice to provide backwards compatibility.See: http://mail.openjdk.java.net/pipermail/hotspot-dev/2012-November/007309.html
The default strategy is NoPadding. In order to apply padding:
import monix.execution.atomic.Atomic import monix.execution.atomic.PaddingStrategy.Right64 val paddedAtomic = Atomic.withPadding(10, Right64)
Value Members
- object Atomic extends Serializable
- object AtomicAny extends Serializable
- object AtomicBoolean extends Serializable
- object AtomicBuilder extends Level2 with Serializable
- object AtomicByte extends Serializable
- object AtomicChar extends Serializable
- object AtomicDouble extends Serializable
- object AtomicFloat extends Serializable
- object AtomicInt extends Serializable
- object AtomicLong extends Serializable
- object AtomicNumberAny extends Serializable
- object AtomicShort extends Serializable
- object PaddingStrategy
This is the API documentation for the Monix library.
Package Overview
monix.execution exposes lower level primitives for dealing with asynchronous execution:
Atomic
types, as alternative tojava.util.concurrent.atomic
monix.catnap exposes pure abstractions built on top of the Cats-Effect type classes:
monix.eval is for dealing with evaluation of results, thus exposing Task and Coeval.
monix.reactive exposes the
Observable
pattern:Observable
implementationsmonix.tail exposes Iterant for purely functional pull based streaming:
Batch
andBatchCursor
, the alternatives to Scala'sIterable
andIterator
respectively that we are using within Iterant's encodingYou can control evaluation with type you choose - be it Task, Coeval, cats.effect.IO or your own as long as you provide correct cats-effect or cats typeclass instance.