A thread-safe, concurrent mutable reference.
Provides safe concurrent access and modification of its content, but no
functionality for synchronisation, which is instead handled by Deferred.
For this reason, a Ref is always initialised to a value.
The default implementation is nonblocking and lightweight, consisting essentially
of a purely functional wrapper over an AtomicReference.
- Companion
- object
Value members
Abstract methods
Obtains a snapshot of the current value, and a setter for updating it.
The setter may noop (in which case false is returned) if another concurrent
call to access uses its setter first.
Obtains a snapshot of the current value, and a setter for updating it.
The setter may noop (in which case false is returned) if another concurrent
call to access uses its setter first.
Once it has noop'd or been used once, a setter never succeeds again.
Satisfies:
r.access.map(_._1) == r.get
r.access.flatMap { case (v, setter) => setter(f(v)) } == r.tryUpdate(f).map(_.isDefined)
Like tryModify but does not complete until the update has been successfully made.
Like tryModify but does not complete until the update has been successfully made.
Like tryModifyState but retries the modification until successful.
Like tryModifyState but retries the modification until successful.
Like tryUpdate but allows the update function to return an output value of
type B. The returned action completes with None if the value is not updated
successfully and Some(b) otherwise.
Like tryUpdate but allows the update function to return an output value of
type B. The returned action completes with None if the value is not updated
successfully and Some(b) otherwise.
Update the value of this ref with a state computation.
Update the value of this ref with a state computation.
The current value of this ref is used as the initial state and the computed output state
is stored in this ref after computation completes. If a concurrent modification occurs,
None is returned.
Attempts to modify the current value once, returning false if another
concurrent modification completes between the time the variable is
read and the time it is set.
Attempts to modify the current value once, returning false if another
concurrent modification completes between the time the variable is
read and the time it is set.
Modifies the current value using the supplied update function. If another modification
occurs between the time the current value is read and subsequently updated, the modification
is retried using the new value. Hence, f may be invoked multiple times.
Modifies the current value using the supplied update function. If another modification
occurs between the time the current value is read and subsequently updated, the modification
is retried using the new value. Hence, f may be invoked multiple times.
Satisfies:
r.update(_ => a) == r.set(a)
Concrete methods
Replaces the current value with a, returning the previous value.
Replaces the current value with a, returning the previous value.
Updates the current value using f and returns the previous value.
Updates the current value using f and returns the previous value.
In case of retries caused by concurrent modifications, the returned value will be the last one before a successful update.
Inherited methods
Obtains the current value.
Obtains the current value.
Since Ref is always guaranteed to have a value, the returned action
completes immediately after being bound.
- Inherited from
- RefSource