Represents an asynchronous computation whose execution can be canceled.
A Scheduler is an scala.concurrent.ExecutionContext
that additionally can schedule
the execution of units of work to run with a delay or periodically.
A Scheduler is an scala.concurrent.ExecutionContext
that additionally can schedule
the execution of units of work to run with a delay or periodically.
Represents a ThreadLocal, a concept that isn't useful on top of a Javascript runtime (since in a JS runtime all variables are thread-local, since it's a single threaded execution model), but having this is useful for cross-compilation purposes.
A small toolkit of classes that support compare-and-swap semantics for mutation of variables.
A small toolkit of classes that support compare-and-swap semantics for mutation of variables.
On top of the JVM, this means dealing with lock-free thread-safe programming.
On top of Javascript / Scala.js using Atomic
references is still good because:
1. boxing values in a smart reference with nice helpers for transformations is always a good idea.
2. on the JVM there are times when synchronization, and when used for synchronization, atomic
references can now cross compile to Scala.js
3. compareAndSet
is actually a good idea to have even in an asynchronous, non-multi-threaded
environment, such as Javascript, because it takes time into account and time related problems
can happen even without multi-threading
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. In comparison with the JVM version,
these Atomic
references do not have methods for weakly setting values (i.e. weakCompareAndSet
, lazySet
),
since those really make no sense in Javascript.
Building a reference is easy with the provided constructor, which will automatically return the most specific type needed:
val atomicNumber = Atomic(12L) atomicNumber.incrementAndGet()
In comparison with java.util.concurrent.AtomicReference
, these references implement common interfaces
that you can use generically (i.e. Atomic[T]
, AtomicNumber[T]
). And also provide useful helpers for
atomically mutating of values (i.e. transform
, transformAndGet
, getAndTransform
, etc...).
Other differences with the JVM-variant - in Scala.js you do not have access to the methods meant to
block (spin-lock) the current thread (e.g. waitForCompareAndSet
, waitForCondition
, etc...), as
the semantics of those operations aren't possible on top of Scala.js
Package provided for Scala.js for source-level compatibility.
Package provided for Scala.js for source-level compatibility. Usage of these locks in Scala.js does not imply any overhead.
Represents an asynchronous computation whose execution can be canceled. Used by monifu.concurrent.Scheduler giving you the ability to cancel scheduled units of work.
It is equivalent to
java.io.Closeable
, but without the I/O focus, or toIDisposable
in Microsoft .NET, or toakka.actor.Cancellable
.