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Interruptible-Cancellable-scala.concurrent.Future
/*
Copyright 2018 Viktor Klang
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
import scala.concurrent._
import java.util.concurrent.CancellationException
final class Interrupt extends (() => Boolean) {
private[this] final var state: AnyRef = null
override final def apply(): Boolean = this.synchronized {
state match {
case null =>
state = this
true
case _: this.type => false
case t: Thread =>
state = this
t.interrupt()
true
}
}
private[this] final def enter(): Boolean =
this.synchronized {
state match {
case _: this.type => false
case null =>
state = Thread.currentThread
true
}
}
private[this] final def exit(): Boolean =
this.synchronized {
state match {
case _: this.type => false
case t: Thread =>
state = this
true
}
}
def interruptibly[T](body: =>T): T =
if (enter()) {
try body catch {
case ie: InterruptedException => throw new CancellationException()
} finally {
if(!exit() && Thread.interrupted())
() // If we were interrupted and flag was not cleared
}
} else throw new CancellationException()
}
def interruptibly[T](body: => T)(implicit ec: ExecutionContext): (Future[T], () => Boolean) = {
val interrupt = new Interrupt()
(Future(interrupt.interruptibly(body))(ec), interrupt)
}
@viktorklang
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viktorklang commented Jun 28, 2016

@Tolsi You should introspect the Future provided to the function to determine whether you want to run or not.

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