MVar

A mutable location, that is either empty or contains a value of type A.

It has 2 fundamental atomic operations:

put which fills the var if empty, or blocks (asynchronously) until the var is empty again
take which empties the var if full, returning the contained value, or blocks (asynchronously) otherwise until there is a value to pull

The MVar is appropriate for building synchronization primitives and performing simple inter-thread communications. If it helps, it's similar with a BlockingQueue(capacity = 1), except that it doesn't block any threads, all waiting being done asynchronously by means of Task.

Given its asynchronous, non-blocking nature, it can be used on top of Javascript as well.

Inspired by Control.Concurrent.MVar from Haskell and by scalaz.concurrent.MVar.

Linear Supertypes

AnyRef, Any

Instance Constructors

new MVar()

Abstract Value Members

abstract def put(a: A): Task[Unit]

Fills the MVar if it is empty, or blocks (asynchronously) if the MVar is full, until the given value is next in line to be consumed on take.
Fills the MVar if it is empty, or blocks (asynchronously) if the MVar is full, until the given value is next in line to be consumed on take.
This operation is atomic. *
returns
a task that on evaluation will complete when the put operation succeeds in filling the MVar, with the given value being next in line to be consumed
abstract def read: Task[A]

Tries reading the current value, or blocks (asynchronously) until there is a value available, at which point the operation resorts to a take followed by a put.
Tries reading the current value, or blocks (asynchronously) until there is a value available, at which point the operation resorts to a take followed by a put.
This read operation is equivalent to:
```
for (a <- v.take; _ <- v.put(a)) yield a
```
This operation is not atomic. Being equivalent with a take followed by a put, in order to ensure that no race conditions happen, additional synchronization is necessary. See TaskSemaphore for a possible solution.
returns
a task that on evaluation will be completed after a value has been read
abstract def take: Task[A]

Empties the MVar if full, returning the contained value, or blocks (asynchronously) until a value is available.
Empties the MVar if full, returning the contained value, or blocks (asynchronously) until a value is available.
This operation is atomic.
returns
a task that on evaluation will be completed after a value was retrieved

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

Definition Classes
AnyRef → Any
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
final def ne(arg0: AnyRef): Boolean

Definition Classes
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final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
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final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
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def toString(): String

Definition Classes
AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

Related Docs: object MVar | package eval

abstract class MVar[A] extends AnyRef

Instance Constructors

new MVar()

Abstract Value Members

abstract def put(a: A): Task[Unit]

abstract def read: Task[A]

abstract def take: Task[A]

Concrete Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def clone(): AnyRef

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

final def getClass(): Class[_]

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

Inherited from AnyRef

Inherited from Any

Ungrouped