Class ScalarSubscription<T>
java.lang.Object
java.lang.Number
java.util.concurrent.atomic.AtomicInteger
io.reactivex.rxjava3.internal.subscriptions.ScalarSubscription<T>
- Type Parameters:
T
- the value type
- All Implemented Interfaces:
QueueFuseable<T>
,QueueSubscription<T>
,SimpleQueue<T>
,Serializable
,org.reactivestreams.Subscription
A Subscription that holds a constant value and emits it only when requested.
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescription(package private) static final int
Cancel has been called.(package private) static final int
No request has been issued yet.(package private) static final int
Request has been called.private static final long
(package private) final org.reactivestreams.Subscriber
<? super T> The actual subscriber.(package private) final T
The single value to emit, set to null. -
Constructor Summary
ConstructorsConstructorDescriptionScalarSubscription
(org.reactivestreams.Subscriber<? super T> subscriber, T value) -
Method Summary
Modifier and TypeMethodDescriptionvoid
cancel()
void
clear()
Removes all enqueued items from this queue.boolean
Returns true if this Subscription was cancelled.boolean
isEmpty()
Returns true if the queue is empty.boolean
Atomically enqueue a single value.boolean
Atomically enqueue two values.poll()
Tries to dequeue a value (non-null) or returns null if the queue is empty.void
request
(long n) int
requestFusion
(int mode) Request a fusion mode from the upstream.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
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Field Details
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serialVersionUID
private static final long serialVersionUID- See Also:
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value
The single value to emit, set to null. -
subscriber
The actual subscriber. -
NO_REQUEST
static final int NO_REQUESTNo request has been issued yet.- See Also:
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REQUESTED
static final int REQUESTEDRequest has been called.- See Also:
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CANCELLED
static final int CANCELLEDCancel has been called.- See Also:
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Constructor Details
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ScalarSubscription
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Method Details
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request
public void request(long n) - Specified by:
request
in interfaceorg.reactivestreams.Subscription
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cancel
public void cancel()- Specified by:
cancel
in interfaceorg.reactivestreams.Subscription
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isCancelled
public boolean isCancelled()Returns true if this Subscription was cancelled.- Returns:
- true if this Subscription was cancelled
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offer
Description copied from interface:SimpleQueue
Atomically enqueue a single value.- Specified by:
offer
in interfaceSimpleQueue<T>
- Parameters:
e
- the value to enqueue, not null- Returns:
- true if successful, false if the value was not enqueued likely due to reaching the queue capacity)
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offer
Description copied from interface:SimpleQueue
Atomically enqueue two values.- Specified by:
offer
in interfaceSimpleQueue<T>
- Parameters:
v1
- the first value to enqueue, not nullv2
- the second value to enqueue, not null- Returns:
- true if successful, false if the value was not enqueued likely due to reaching the queue capacity)
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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.- Specified by:
poll
in interfaceSimpleQueue<T>
- Returns:
- the item or null to indicate an empty queue
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isEmpty
public 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).- Specified by:
isEmpty
in interfaceSimpleQueue<T>
- Returns:
- true if the queue is empty
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clear
public void clear()Description copied from interface:SimpleQueue
Removes all enqueued items from this queue.- Specified by:
clear
in interfaceSimpleQueue<T>
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requestFusion
public 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.- Specified by:
requestFusion
in interfaceQueueFuseable<T>
- 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
.
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