Core primitives to work with coroutines.
Coroutine builder functions:
Name | Result | Scope | Description |
---|---|---|---|
launch | Job | CoroutineScope | Launches coroutine that does not have any result |
async | Deferred | CoroutineScope | Returns a single value with the future result |
produce | ReceiveChannel | ProducerScope | Produces a stream of elements |
actor | SendChannel | ActorScope | Processes a stream of messages |
runBlocking | T |
CoroutineScope | Blocks the thread while the coroutine runs |
Coroutine dispatchers implementing CoroutineDispatcher:
Name | Description |
---|---|
DefaultDispatcher | Is equal to CommonPool |
CommonPool | Confines coroutine execution to a shared pool of threads |
newSingleThreadContext | Create new single-threaded coroutine context |
newFixedThreadPoolContext | Creates new thread pool of a fixed size |
Executor.asCoroutineDispatcher | Extension to convert any executor |
Unconfined | Does not confine coroutine execution in any way |
More context elements:
Name | Description |
---|---|
NonCancellable | A non-cancelable job that is always active |
CoroutineExceptionHandler | Handler for uncaught exception |
Synchronization primitives for coroutines:
Name | Suspending functions | Description |
---|---|---|
Mutex | lock | Mutual exclusion |
Channel | send, receive | Communication channel (aka queue or exchanger) |
Top-level suspending functions:
Name | Description |
---|---|
delay | Non-blocking sleep |
yield | Yields thread in single-threaded dispatchers |
withContext | Switches to a different context |
withTimeout | Set execution time-limit with exception on timeout |
withTimeoutOrNull | Set execution time-limit will null result on timeout |
Select expression waits for the result of multiple suspending functions simultaneously:
Receiver | Suspending function | Select clause | Non-suspending version |
---|---|---|---|
Job | join | onJoin | isCompleted |
Deferred | await | onAwait | isCompleted |
SendChannel | send | onSend | offer |
ReceiveChannel | receive | onReceive | poll |
ReceiveChannel | receiveOrNull | onReceiveOrNull | poll |
Mutex | lock | onLock | tryLock |
none | delay | onTimeout | none |
Cancellation support for user-defined suspending functions is available with suspendCancellableCoroutine
helper function. NonCancellable job object is provided to suppress cancellation with
run(NonCancellable) {...}
block of code.
This module provides debugging facilities for coroutines (run JVM with -ea
or -Dkotlinx.coroutines.debug
options)
and newCoroutineContext function to write user-defined coroutine builders that work with these
debugging facilities.
Packages
General-purpose coroutine builders, contexts, and helper functions. |
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Channels – non-blocking primitives for communicating a stream of elements between coroutines. |
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Low-level primitives for finer-grained control of coroutines. |
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Select expression to perform multiple suspending operations simultaneously until one of them succeeds. |
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Synchronization primitives (mutex). |