concurrent
Processes messages of type A, one at a time.
Future is a trampolined computation producing an A that may
include asynchronous steps.
Future is a trampolined computation producing an A that may
include asynchronous steps. Like Trampoline, arbitrary
monadic expressions involving map and flatMap are guaranteed
to use constant stack space. But in addition, one may construct a
Future from an asynchronous computation, represented as a
function, listen: (A => Unit) => Unit, which registers a callback
that will be invoked when the result becomes available. This makes
Future useful as a concurrency primitive and as a control
structure for wrapping callback-based APIs with a more
straightforward, monadic API.
Unlike the Future implementation in scala 2.10, map and
flatMap do NOT spawn new tasks and do not require an implicit
ExecutionContext. Instead, map and flatMap merely add to
the current (trampolined) continuation that will be run by the
'current' thread, unless explicitly forked via Future.fork or
Future.apply. This means that Future achieves much better thread
reuse than the 2.10 implementation and avoids needless thread
pool submit cycles.
Future also differs from the scala 2.10 Future type in that it
does not necessarily represent a _running_ computation. Instead, we
reintroduce nondeterminism _explicitly_ using the functions of the
scalaz.Nondeterminism interface. This simplifies our implementation
and makes code easier to reason about, since the order of effects
and the points of nondeterminism are made fully explicit and do not
depend on Scala's evaluation order.
IMPORTANT NOTE: Future does not include any error handling and
should generally only be used as a building block by library
writers who want to build on Future's capabilities but wish to
design their own error handling strategy. See
scalaz.concurrent.Task for a type that extends Future with
proper error handling -- it is merely a wrapper for
Future[Throwable \/ A] with a number of additional
convenience functions.
Evaluate an expression in some specific manner.
Evaluate an expression in some specific manner. A typical strategy will schedule asynchronous evaluation and return a function that, when called, will block until the result is ready.
Memory consistency effects: Actions in a thread prior to the submission of a
to the Strategy happen-before any actions taken by a, which in turn happen-before
the result is retrieved via returned function.
(Since version 7.1) use Future or other concurrency abstractions
(Since version 7.1) use Future or other concurrency abstractions
(Since version 7.1) use Future or other concurrency abstractions
(Since version 7.1) use Future or other concurrency abstractions
Processes messages of type
A, one at a time. Messages are submitted to the actor with the method!. Processing is typically performed asynchronously, this is controlled by the providedstrategy.Memory consistency guarantee: when each message is processed by the
handler, any memory that it mutates is guaranteed to be visible by thehandlerwhen it processes the next message, even if thestrategyruns the invocations ofhandleron separate threads. This is achieved because theActorreads a volatile memory location before entering its event loop, and writes to the same location before suspending.Implementation based on non-intrusive MPSC node-based queue, described by Dmitriy Vyukov: http://www.1024cores.net/home/lock-free-algorithms/queues/non-intrusive-mpsc-node-based-queue
The type of messages accepted by this actor.
The message handler
Exception handler, called if the message handler throws any
Throwable.Execution strategy, for example, a strategy that is backed by an
ExecutorServicescalaz.concurrent.Promise for a use case.