Class DeferredScalarSubscription<T>
- Type Parameters:
T
- the value type
- All Implemented Interfaces:
QueueFuseable<T>
,QueueSubscription<T>
,SimpleQueue<T>
,Serializable
,org.reactivestreams.Subscription
- Direct Known Subclasses:
AsyncProcessor.AsyncSubscription
,DeferredScalarSubscriber
,FlowableAll.AllSubscriber
,FlowableAny.AnySubscriber
,FlowableCollect.CollectSubscriber
,FlowableCollectWithCollector.CollectorSubscriber
,FlowableCount.CountSubscriber
,FlowableElementAt.ElementAtSubscriber
,FlowableFromCompletionStage.CompletionStageHandler
,FlowableReduce.ReduceSubscriber
,FlowableSequenceEqual.EqualCoordinator
,FlowableSingle.SingleElementSubscriber
,FlowableTakeLastOne.TakeLastOneSubscriber
,FlowableToList.ToListSubscriber
,MaybeToFlowable.MaybeToFlowableSubscriber
,ParallelCollector.ParallelCollectorSubscriber
,ParallelReduceFull.ParallelReduceFullMainSubscriber
,SingleToFlowable.SingleToFlowableObserver
Note that the class leaks all methods of AtomicLong
.
Use complete(Object)
to signal the single value.
The this atomic integer stores a bit field:
bit 0: indicates that there is a value available
bit 1: indicates that there was a request made
bit 2: indicates there was a cancellation, exclusively set
bit 3: indicates in fusion mode but no value yet, exclusively set
bit 4: indicates in fusion mode and value is available, exclusively set
bit 5: indicates in fusion mode and value has been consumed, exclusively set
Where exclusively set means any other bits are 0 when that bit is set.
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescription(package private) static final int
Indicates the Subscription has been cancelled.protected final org.reactivestreams.Subscriber
<? super T> The Subscriber to emit the value to.(package private) static final int
Indicates this Subscription is in fusion mode and its value has been consumed.(package private) static final int
Indicates this Subscription is in fusion mode and is currently empty.(package private) static final int
Indicates this Subscription is in fusion mode and has a value.(package private) static final int
Indicates this Subscription has both request and value.(package private) static final int
Indicates this Subscription has been requested but there is no value yet.(package private) static final int
Indicates this Subscription has a value but not requested yet.(package private) static final int
Indicates this Subscription has no value and not requested yet.private static final long
protected T
The value is stored here if there is no request yet or in fusion mode. -
Constructor Summary
ConstructorsConstructorDescriptionDeferredScalarSubscription
(org.reactivestreams.Subscriber<? super @NonNull T> downstream) Creates a DeferredScalarSubscription by wrapping the given Subscriber. -
Method Summary
Modifier and TypeMethodDescriptionvoid
cancel()
final void
clear()
Removes all enqueued items from this queue.final void
Completes this subscription by indicating the given value should be emitted when the first request arrives.final boolean
Returns true if this Subscription has been cancelled.final boolean
isEmpty()
Returns true if the queue is empty.final T
poll()
Tries to dequeue a value (non-null) or returns null if the queue is empty.final void
request
(long n) final int
requestFusion
(int mode) Request a fusion mode from the upstream.final boolean
Atomically sets a cancelled state and returns true if the current thread did it successfully.Methods inherited from class io.reactivex.rxjava3.internal.subscriptions.BasicIntQueueSubscription
offer, offer
Methods inherited from class java.util.concurrent.atomic.AtomicInteger
accumulateAndGet, addAndGet, compareAndExchange, compareAndExchangeAcquire, compareAndExchangeRelease, compareAndSet, decrementAndGet, doubleValue, floatValue, get, getAcquire, getAndAccumulate, getAndAdd, getAndDecrement, getAndIncrement, getAndSet, getAndUpdate, getOpaque, getPlain, incrementAndGet, intValue, lazySet, longValue, set, setOpaque, setPlain, setRelease, toString, updateAndGet, weakCompareAndSet, weakCompareAndSetAcquire, weakCompareAndSetPlain, weakCompareAndSetRelease, weakCompareAndSetVolatile
Methods inherited from class java.lang.Number
byteValue, shortValue
-
Field Details
-
serialVersionUID
private static final long serialVersionUID- See Also:
-
downstream
The Subscriber to emit the value to. -
value
The value is stored here if there is no request yet or in fusion mode. -
NO_REQUEST_NO_VALUE
static final int NO_REQUEST_NO_VALUEIndicates this Subscription has no value and not requested yet.- See Also:
-
NO_REQUEST_HAS_VALUE
static final int NO_REQUEST_HAS_VALUEIndicates this Subscription has a value but not requested yet.- See Also:
-
HAS_REQUEST_NO_VALUE
static final int HAS_REQUEST_NO_VALUEIndicates this Subscription has been requested but there is no value yet.- See Also:
-
HAS_REQUEST_HAS_VALUE
static final int HAS_REQUEST_HAS_VALUEIndicates this Subscription has both request and value.- See Also:
-
CANCELLED
static final int CANCELLEDIndicates the Subscription has been cancelled.- See Also:
-
FUSED_EMPTY
static final int FUSED_EMPTYIndicates this Subscription is in fusion mode and is currently empty.- See Also:
-
FUSED_READY
static final int FUSED_READYIndicates this Subscription is in fusion mode and has a value.- See Also:
-
FUSED_CONSUMED
static final int FUSED_CONSUMEDIndicates this Subscription is in fusion mode and its value has been consumed.- See Also:
-
-
Constructor Details
-
DeferredScalarSubscription
Creates a DeferredScalarSubscription by wrapping the given Subscriber.- Parameters:
downstream
- the Subscriber to wrap, not null (not verified)
-
-
Method Details
-
request
public final void request(long n) -
complete
Completes this subscription by indicating the given value should be emitted when the first request arrives.Make sure this is called exactly once.
- Parameters:
v
- the value to signal, not null (not validated)
-
requestFusion
public final int requestFusion(int mode) Description copied from interface:QueueFuseable
Request a fusion mode from the upstream.This should be called before
onSubscribe
returns.Calling this method multiple times or after
onSubscribe
finished is not allowed and may result in undefined behavior.- Parameters:
mode
- the requested fusion mode, allowed values areQueueFuseable.SYNC
,QueueFuseable.ASYNC
,QueueFuseable.ANY
combined withQueueFuseable.BOUNDARY
(e.g.,requestFusion(SYNC | BOUNDARY)
).- Returns:
- the established fusion mode:
QueueFuseable.NONE
,QueueFuseable.SYNC
,QueueFuseable.ASYNC
.
-
poll
Description copied from interface:SimpleQueue
Tries to dequeue a value (non-null) or returns null if the queue is empty.If the producer uses
SimpleQueue.offer(Object, Object)
and when polling in pairs, if the first poll() returns a non-null item, the second poll() is guaranteed to return a non-null item as well.- Returns:
- the item or null to indicate an empty queue
-
isEmpty
public final boolean isEmpty()Description copied from interface:SimpleQueue
Returns true if the queue is empty.Note however that due to potential fused functions in
SimpleQueue.poll()
it is possible this method returns false but then poll() returns null because the fused function swallowed the available item(s).- Returns:
- true if the queue is empty
-
clear
public final void clear()Description copied from interface:SimpleQueue
Removes all enqueued items from this queue. -
cancel
public void cancel() -
isCancelled
public final boolean isCancelled()Returns true if this Subscription has been cancelled.- Returns:
- true if this Subscription has been cancelled
-
tryCancel
public final boolean tryCancel()Atomically sets a cancelled state and returns true if the current thread did it successfully.- Returns:
- true if the current thread cancelled
-