sealed abstract
class
FrameIndexRef extends AnyRef
Abstract Value Members
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abstract
def
apply(): FrameIndex
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abstract
def
reset(): Unit
Concrete Value Members
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final
def
!=(arg0: Any): Boolean
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final
def
##(): Int
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final
def
==(arg0: Any): Boolean
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final
def
asInstanceOf[T0]: T0
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def
clone(): AnyRef
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def
finalize(): Unit
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final
def
getClass(): Class[_]
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def
hashCode(): Int
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final
def
isInstanceOf[T0]: Boolean
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final
def
notify(): Unit
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final
def
notifyAll(): Unit
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final
def
synchronized[T0](arg0: ⇒ T0): T0
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def
toString(): String
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final
def
wait(): Unit
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final
def
wait(arg0: Long, arg1: Int): Unit
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final
def
wait(arg0: Long): Unit
A reference that boxes a FrameIndex possibly using a thread-local.
This definition is of interest only when creating tasks with Task.unsafeCreate, which exposes internals and is considered unsafe to use.
In case the Task is executed with BatchedExecution, this class boxes a FrameIndex in order to transport it over light async boundaries, possibly using a ThreadLocal, since this index is not supposed to survive when threads get forked.
The FrameIndex is a counter that increments whenever a
flatMap
operation is evaluated. And withBatchedExecution
, whenever that counter exceeds the specified threshold, an asynchronous boundary is automatically inserted. However this capability doesn't blend well with light asynchronous boundaries, for exampleAsync
tasks that never fork logical threads or TrampolinedRunnable instances executed by capable schedulers. This is why FrameIndexRef is part of the Context of execution for Task, available for asynchronous tasks that get created with Task.unsafeCreate.Note that in case the execution model is not BatchedExecution then this reference is just a dummy, since there's no point in keeping a counter around, plus setting and fetching from a
ThreadLocal
can be quite expensive.