| /* |
| * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license. |
| */ |
| |
| package kotlinx.coroutines |
| |
| import java.util.concurrent.* |
| import java.util.concurrent.atomic.AtomicInteger |
| |
| /** |
| * Creates a coroutine execution context using a single thread with built-in [yield] support. |
| * **NOTE: The resulting [ExecutorCoroutineDispatcher] owns native resources (its thread). |
| * Resources are reclaimed by [ExecutorCoroutineDispatcher.close].** |
| * |
| * If the resulting dispatcher is [closed][ExecutorCoroutineDispatcher.close] and |
| * attempt to submit a continuation task is made, |
| * then the [Job] of the affected task is [cancelled][Job.cancel] and the task is submitted to the |
| * [Dispatchers.IO], so that the affected coroutine can cleanup its resources and promptly complete. |
| * |
| * This is a **delicate** API. The result of this method is a closeable resource with the |
| * associated native resources (threads). It should not be allocated in place, |
| * should be closed at the end of its lifecycle, and has non-trivial memory and CPU footprint. |
| * If you do not need a separate thread-pool, but only have to limit effective parallelism of the dispatcher, |
| * it is recommended to use [CoroutineDispatcher.limitedParallelism] instead. |
| * |
| * If you need a completely separate thread-pool with scheduling policy that is based on the standard |
| * JDK executors, use the following expression: |
| * `Executors.newSingleThreadExecutor().asCoroutineDispatcher()`. |
| * See [Executor.asCoroutineDispatcher] for details. |
| * |
| * @param name the base name of the created thread. |
| */ |
| @DelicateCoroutinesApi |
| public actual fun newSingleThreadContext(name: String): ExecutorCoroutineDispatcher = |
| newFixedThreadPoolContext(1, name) |
| |
| /** |
| * Creates a coroutine execution context with the fixed-size thread-pool and built-in [yield] support. |
| * **NOTE: The resulting [ExecutorCoroutineDispatcher] owns native resources (its threads). |
| * Resources are reclaimed by [ExecutorCoroutineDispatcher.close].** |
| * |
| * If the resulting dispatcher is [closed][ExecutorCoroutineDispatcher.close] and |
| * attempt to submit a continuation task is made, |
| * then the [Job] of the affected task is [cancelled][Job.cancel] and the task is submitted to the |
| * [Dispatchers.IO], so that the affected coroutine can cleanup its resources and promptly complete. |
| * |
| * This is a **delicate** API. The result of this method is a closeable resource with the |
| * associated native resources (threads). It should not be allocated in place, |
| * should be closed at the end of its lifecycle, and has non-trivial memory and CPU footprint. |
| * If you do not need a separate thread-pool, but only have to limit effective parallelism of the dispatcher, |
| * it is recommended to use [CoroutineDispatcher.limitedParallelism] instead. |
| * |
| * If you need a completely separate thread-pool with scheduling policy that is based on the standard |
| * JDK executors, use the following expression: |
| * `Executors.newFixedThreadPool().asCoroutineDispatcher()`. |
| * See [Executor.asCoroutineDispatcher] for details. |
| * |
| * @param nThreads the number of threads. |
| * @param name the base name of the created threads. |
| */ |
| @DelicateCoroutinesApi |
| public actual fun newFixedThreadPoolContext(nThreads: Int, name: String): ExecutorCoroutineDispatcher { |
| require(nThreads >= 1) { "Expected at least one thread, but $nThreads specified" } |
| val threadNo = AtomicInteger() |
| val executor = Executors.newScheduledThreadPool(nThreads) { runnable -> |
| val t = Thread(runnable, if (nThreads == 1) name else name + "-" + threadNo.incrementAndGet()) |
| t.isDaemon = true |
| t |
| } |
| return executor.asCoroutineDispatcher() |
| } |