public static interface Sinks.One<T> extends Sinks.Empty<T>
Sinks
with Mono
semantics.
The sink can be exposed to consuming code as a Mono
via its Sinks.Empty.asMono()
view.
Scannable.Attr<T>
OPERATOR_NAME_UNRELATED_WORDS_PATTERN
Modifier and Type | Method and Description |
---|---|
void |
emitValue(T value,
Sinks.EmitFailureHandler failureHandler)
A simplified attempt at emitting a non-null element via the
tryEmitValue(Object) API, generating an
onNext signal immediately followed by an Subscriber.onComplete() signal. |
Sinks.EmitResult |
tryEmitValue(T value)
Try to complete the
Mono with an element, generating an onNext signal
immediately followed by an onComplete signal. |
asMono, currentSubscriberCount, emitEmpty, emitError, tryEmitEmpty, tryEmitError
actuals, from, inners, isScanAvailable, name, parents, scan, scanOrDefault, scanUnsafe, stepName, steps, tags
Sinks.EmitResult tryEmitValue(@Nullable T value)
Mono
with an element, generating an onNext
signal
immediately followed by an onComplete
signal. A null
value
will only trigger the onComplete. The result of the attempt is represented as an Sinks.EmitResult
,
which possibly indicates error cases.
See the list of failure Sinks.EmitResult
in #emitValue(Object, EmitFailureHandler)
javadoc for an
example of how each of these can be dealt with, to decide if the emit API would be a good enough fit instead.
Might throw an unchecked exception as a last resort (eg. in case of a fatal error downstream which cannot be propagated to any asynchronous handler, a bubbling exception, ...).
value
- the value to emit and complete with, or null
to only trigger an onCompleteSinks.EmitResult
, which should be checked to distinguish different possible failuresemitValue(Object, Sinks.EmitFailureHandler)
,
Subscriber.onNext(Object)
,
Subscriber.onComplete()
void emitValue(@Nullable T value, Sinks.EmitFailureHandler failureHandler)
tryEmitValue(Object)
API, generating an
onNext
signal immediately followed by an Subscriber.onComplete()
signal.
If the result of the attempt is not a success
, implementations SHOULD retry the
tryEmitValue(Object)
call IF the provided Sinks.EmitFailureHandler
returns true
.
Otherwise, failures are dealt with in a predefined way that might depend on the actual sink implementation
(see below for the vanilla reactor-core behavior).
Generally, tryEmitValue(Object)
is preferable since it allows a custom handling
of error cases, although this implies checking the returned Sinks.EmitResult
and correctly
acting on it. This API is intended as a good default for convenience.
When the Sinks.EmitResult
is not a success, vanilla reactor-core operators have the following behavior:
Sinks.EmitResult.FAIL_ZERO_SUBSCRIBER
: no particular handling. should ideally discard the value but at that
point there's no Subscriber
from which to get a contextual discard handler.
Sinks.EmitResult.FAIL_OVERFLOW
: discard the value (Operators.onDiscard(Object, Context)
)
then call Sinks.Empty.emitError(Throwable, Sinks.EmitFailureHandler)
with a Exceptions.failWithOverflow(String)
exception.
Sinks.EmitResult.FAIL_CANCELLED
: discard the value (Operators.onDiscard(Object, Context)
).
Sinks.EmitResult.FAIL_TERMINATED
: drop the value (Operators.onNextDropped(Object, Context)
).
Sinks.EmitResult.FAIL_NON_SERIALIZED
: throw an Sinks.EmissionException
mentioning RS spec rule 1.3.
Note that Sinks.unsafe()
never trigger this result. It would be possible for an Sinks.EmitFailureHandler
to busy-loop and optimistically wait for the contention to disappear to avoid this case for safe sinks...
Might throw an unchecked exception as a last resort (eg. in case of a fatal error downstream which cannot
be propagated to any asynchronous handler, a bubbling exception, a Sinks.EmitResult.FAIL_NON_SERIALIZED
as described above, ...).
value
- the value to emit and complete with, a null
is actually acceptable to only trigger an onCompletefailureHandler
- the failure handler that allows retrying failed Sinks.EmitResult
.Sinks.EmissionException
- on non-serialized accesstryEmitValue(Object)
,
Subscriber.onNext(Object)
,
Subscriber.onComplete()