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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.concurrent.impl
import java.util.concurrent.{ LinkedBlockingQueue, Callable, Executor, ExecutorService, Executors, ThreadFactory, TimeUnit, ThreadPoolExecutor }
import java.util.Collection
import scala.concurrent.forkjoin._
import scala.concurrent.{ BlockContext, ExecutionContext, Awaitable, CanAwait, ExecutionContextExecutor, ExecutionContextExecutorService }
import scala.util.control.NonFatal
private[scala] class ExecutionContextImpl private[impl] (es: Executor, reporter: Throwable => Unit) extends ExecutionContextExecutor {
val executor: Either[ForkJoinPool, Executor] = es match {
case null => createExecutor
case some => Right(some)
}
// Implement BlockContext on FJP threads
class DefaultThreadFactory(daemonic: Boolean) extends ThreadFactory with ForkJoinPool.ForkJoinWorkerThreadFactory {
def wire[T <: Thread](thread: T): T = {
thread.setDaemon(daemonic)
//Potentially set things like uncaught exception handler, name etc
thread
}
def newThread(runnable: Runnable): Thread = wire(new Thread(runnable))
def newThread(fjp: ForkJoinPool): ForkJoinWorkerThread = wire(new ForkJoinWorkerThread(fjp) with BlockContext {
override def blockOn[T](thunk: =>T)(implicit permission: CanAwait): T = {
var result: T = null.asInstanceOf[T]
ForkJoinPool.managedBlock(new ForkJoinPool.ManagedBlocker {
@volatile var isdone = false
override def block(): Boolean = {
result = try thunk finally { isdone = true }
true
}
override def isReleasable = isdone
}, true)
result
}
})
}
def createExecutor: Either[ForkJoinPool, Executor] = {
def getInt(name: String, f: String => Int): Int =
try f(System.getProperty(name)) catch { case e: Exception => Runtime.getRuntime.availableProcessors }
def range(floor: Int, desired: Int, ceiling: Int): Int =
if (ceiling < floor) range(ceiling, desired, floor) else scala.math.min(scala.math.max(desired, floor), ceiling)
val desiredParallelism = range(
getInt("scala.concurrent.context.minThreads", _.toInt),
getInt("scala.concurrent.context.numThreads", {
case null | "" => Runtime.getRuntime.availableProcessors
case s if s.charAt(0) == 'x' => (Runtime.getRuntime.availableProcessors * s.substring(1).toDouble).ceil.toInt
case other => other.toInt
}),
getInt("scala.concurrent.context.maxThreads", _.toInt))
val threadFactory = new DefaultThreadFactory(daemonic = true)
try {
val pool = new ForkJoinPool(
desiredParallelism,
threadFactory)
pool.setAsyncMode(true)
Left(pool)
} catch {
case NonFatal(t) =>
System.err.println("Failed to create ForkJoinPool for the default ExecutionContext, falling back to ThreadPoolExecutor")
t.printStackTrace(System.err)
val exec = new ThreadPoolExecutor(
desiredParallelism,
desiredParallelism,
5L,
TimeUnit.MINUTES,
new LinkedBlockingQueue[Runnable],
threadFactory
)
exec.allowCoreThreadTimeOut(true)
Right(exec)
}
}
def execute(runnable: Runnable): Unit = executor match {
case Left(fj) =>
Thread.currentThread match {
case fjw: ForkJoinWorkerThread if fjw.getPool eq fj =>
(runnable match {
case fjt: ForkJoinTask[_] => fjt
case _ => new AdaptedRunnableAction(runnable)
}).fork
case _ => fj.execute(runnable)
}
case Right(generic) => generic execute runnable
}
def reportFailure(t: Throwable) = reporter(t)
}
private[concurrent] object ExecutionContextImpl {
def fromExecutor(e: Executor, reporter: Throwable => Unit = ExecutionContext.defaultReporter): ExecutionContextImpl = new ExecutionContextImpl(e, reporter)
def fromExecutorService(es: ExecutorService, reporter: Throwable => Unit = ExecutionContext.defaultReporter): ExecutionContextImpl with ExecutionContextExecutorService =
new ExecutionContextImpl(es, reporter) with ExecutionContextExecutorService {
final def asExecutorService: ExecutorService = executor.right.asInstanceOf[ExecutorService]
override def execute(command: Runnable) = executor.right.get.execute(command)
override def shutdown() { asExecutorService.shutdown() }
override def shutdownNow() = asExecutorService.shutdownNow()
override def isShutdown = asExecutorService.isShutdown
override def isTerminated = asExecutorService.isTerminated
override def awaitTermination(l: Long, timeUnit: TimeUnit) = asExecutorService.awaitTermination(l, timeUnit)
override def submit[T](callable: Callable[T]) = asExecutorService.submit(callable)
override def submit[T](runnable: Runnable, t: T) = asExecutorService.submit(runnable, t)
override def submit(runnable: Runnable) = asExecutorService.submit(runnable)
override def invokeAll[T](callables: Collection[_ <: Callable[T]]) = asExecutorService.invokeAll(callables)
override def invokeAll[T](callables: Collection[_ <: Callable[T]], l: Long, timeUnit: TimeUnit) = asExecutorService.invokeAll(callables, l, timeUnit)
override def invokeAny[T](callables: Collection[_ <: Callable[T]]) = asExecutorService.invokeAny(callables)
override def invokeAny[T](callables: Collection[_ <: Callable[T]], l: Long, timeUnit: TimeUnit) = asExecutorService.invokeAny(callables, l, timeUnit)
}
}
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