Transforms the source using the given operator function.
Transforms the source using the given transformer function.
Concatenates the source with another observable.
Concatenates the source with another observable.
Ordering of subscription is preserved, so the second observable
starts only after the source observable is completed
successfully with an onComplete
. On the other hand, the second
observable is never subscribed if the source completes with an
error.
Creates a new Observable that emits the given element and then it also emits the events of the source (prepend operation).
Creates a new Observable that emits the events of the source and then it also emits the given element (appended to the stream).
Given the source observable and another Observable
, emits all of
the items from the first of these Observables to emit an item
and cancel the other.
Forces a buffered asynchronous boundary.
Forces a buffered asynchronous boundary.
Internally it wraps the observer implementation given to
onSubscribe
into a
BufferedSubscriber.
Normally Monix's implementation guarantees that events are
not emitted concurrently, and that the publisher MUST NOT
emit the next event without acknowledgement from the
consumer that it may proceed, however for badly behaved
publishers, this wrapper provides the guarantee that the
downstream Observer given in
subscribe
will not receive concurrent events.
WARNING: if the buffer created by this operator is unbounded, it can blow up the process if the data source is pushing events faster than what the observer can consume, as it introduces an asynchronous boundary that eliminates the back-pressure requirements of the data source. Unbounded is the default overflowStrategy, see OverflowStrategy for options.
- the overflow strategy used for buffering, which specifies what to do in case we're dealing with a slow consumer - should an unbounded buffer be used, should back-pressure be applied, should the pipeline drop newer or older events, should it drop the whole buffer? See OverflowStrategy for more details.
Buffers signals while busy, after which it emits the buffered events as a single bundle.
Buffers signals while busy, after which it emits the buffered events as a single bundle.
This operator starts applying back-pressure when the underlying buffer's size is exceeded.
Returns an observable that emits buffers of items it collects from the source observable.
Returns an observable that emits buffers of items it collects from
the source observable. The resulting observable emits buffers
every skip
items, each containing count
items.
If the source observable completes, then the current buffer gets signaled downstream. If the source triggers an error then the current buffer is being dropped and the error gets propagated immediately.
For count
and skip
there are 3 possibilities:
skip == count
, then there are no items dropped and
no overlap, the call being equivalent to buffer(count)
skip < count
, then overlap between buffers
happens, with the number of elements being repeated being
count - skip
skip > count
, then skip - count
elements start
getting dropped between windows
the maximum size of each buffer before it should be emitted
how many items emitted by the source observable should
be skipped before starting a new buffer. Note that when
skip and count are equal, this is the same operation as
buffer(count)
Periodically gather items emitted by an observable into bundles and emit these bundles rather than emitting the items one at a time.
Periodically gather items emitted by an observable into bundles and emit these bundles rather than emitting the items one at a time.
This version of buffer
emits a new bundle of items
periodically, every timespan amount of time, containing all
items emitted by the source Observable since the previous bundle
emission.
If the source observable completes, then the current buffer gets signaled downstream. If the source triggers an error then the current buffer is being dropped and the error gets propagated immediately.
the interval of time at which it should emit the buffered bundle
Periodically gather items emitted by an observable into bundles and emit these bundles rather than emitting the items one at a time.
Periodically gather items emitted by an observable into bundles and emit these bundles rather than emitting the items one at a time.
The resulting observable emits connected, non-overlapping
buffers, each of a fixed duration specified by the timespan
argument or a maximum size specified by the maxCount
argument
(whichever is reached first).
If the source observable completes, then the current buffer gets signaled downstream. If the source triggers an error then the current buffer is being dropped and the error gets propagated immediately.
the interval of time at which it should emit the buffered bundle
is the maximum bundle size, after which the buffered bundle gets forcefully emitted
Periodically gather items emitted by an observable into bundles and emit these bundles rather than emitting the items one at a time.
Periodically gather items emitted by an observable into bundles and emit these bundles rather than emitting the items one at a time. Back-pressure the source when the buffer is full.
The resulting observable emits connected, non-overlapping
buffers, each of a fixed duration specified by the period
argument.
The bundles are emitted at a fixed rate. If the source is silent, then the resulting observable will start emitting empty sequences.
If the source observable completes, then the current buffer gets signaled downstream. If the source triggers an error then the current buffer is being dropped and the error gets propagated immediately.
A maxSize
argument is specified as the capacity of the
bundle. In case the source is too fast and maxSize
is reached,
then the source will be back-pressured.
The difference with bufferTimedAndCounted is that bufferTimedWithPressure applies back-pressure from the time when the buffer is full until the buffer is emitted, whereas bufferTimedAndCounted will forcefully emit the buffer when it's full.
the interval of time at which it should emit the buffered bundle
is the maximum buffer size, after which the source starts being back-pressured
Periodically gather items emitted by an observable into bundles and emit these bundles rather than emitting the items one at a time.
Periodically gather items emitted by an observable into bundles
and emit these bundles rather than emitting the items one at a
time. This version of buffer
is emitting items once the
internal buffer has reached the given count.
If the source observable completes, then the current buffer gets signaled downstream. If the source triggers an error then the current buffer is being dropped and the error gets propagated immediately.
the maximum size of each buffer before it should be emitted
Periodically gather items emitted by
an observable into bundles and emit these bundles rather than
emitting the items one at a time, whenever the selector
observable signals an event.
Periodically gather items emitted by
an observable into bundles and emit these bundles rather than
emitting the items one at a time, whenever the selector
observable signals an event.
The resulting observable collects the elements of the source
in a buffer and emits that buffer whenever the given selector
observable emits an onNext
event, when the buffer is emitted
as a sequence downstream and then reset. Thus the resulting
observable emits connected, non-overlapping bundles triggered
by the given selector
.
If selector
terminates with an onComplete
, then the resulting
observable also terminates normally. If selector
terminates with
an onError
, then the resulting observable also terminates with an
error.
If the source observable completes, then the current buffer gets signaled downstream. If the source triggers an error then the current buffer is being dropped and the error gets propagated immediately.
A maxSize
argument is specified as the capacity of the
bundle. In case the source is too fast and maxSize
is reached,
then the source will be back-pressured.
is the observable that triggers the signaling of the current buffer
is the maximum bundle size, after which the source starts being back-pressured
Periodically gather items emitted by
an observable into bundles and emit these bundles rather than
emitting the items one at a time, whenever the selector
observable signals an event.
Periodically gather items emitted by
an observable into bundles and emit these bundles rather than
emitting the items one at a time, whenever the selector
observable signals an event.
The resulting observable collects the elements of the source
in a buffer and emits that buffer whenever the given selector
observable emits an onNext
event, when the buffer is emitted
as a sequence downstream and then reset. Thus the resulting
observable emits connected, non-overlapping bundles triggered
by the given selector
.
If selector
terminates with an onComplete
, then the resulting
observable also terminates normally. If selector
terminates with
an onError
, then the resulting observable also terminates with an
error.
If the source observable completes, then the current buffer gets signaled downstream. If the source triggers an error then the current buffer is being dropped and the error gets propagated immediately.
is the observable that triggers the signaling of the current buffer
Applies the given partial function to the source for each element for which the given partial function is defined.
Applies the given partial function to the source for each element for which the given partial function is defined.
the function that filters and maps the source
an observable that emits the transformed items by the given partial function
Creates a new observable from the source and another given observable, by emitting elements combined in pairs.
Creates a new observable from the source and another given observable, by emitting elements combined in pairs. If one of the observables emits fewer events than the other, then the rest of the unpaired events are ignored.
See zip for an alternative that pairs the items in strict sequence.
is an observable that gets paired with the source
Creates a new observable from the source and another given observable, by emitting elements combined in pairs.
Creates a new observable from the source and another given observable, by emitting elements combined in pairs. If one of the observables emits fewer events than the other, then the rest of the unpaired events are ignored.
See zipMap for an alternative that pairs the items in strict sequence.
is an observable that gets paired with the source
is a mapping function over the generated pairs
Ignores all items emitted by the source Observable and only calls onCompleted or onError.
Ignores all items emitted by the source Observable and only calls onCompleted or onError.
an empty Observable that only calls onCompleted or onError, based on which one is called by the source Observable
Concatenates the sequence of observables emitted by the source into one observable, without any transformation.
Concatenates the sequence of observables emitted by the source into one observable, without any transformation.
You can combine the items emitted by multiple observables so that they act like a single sequence by using this operator.
The difference between the concat
operation
and merge
is that concat
cares about the ordering of sequences
(e.g. all items emitted by the first observable in the sequence
will come before the elements emitted by the second observable),
whereas merge
doesn't care about that (elements get
emitted as they come). Because of back-pressure applied to
observables, concat
is safe to use in all contexts, whereas
merge
requires buffering.
an observable that emits items that are the result of flattening the items emitted by the observables emitted by the source
Concatenates the sequence of observables emitted by the source into one observable, without any transformation.
Concatenates the sequence of observables emitted by the source into one observable, without any transformation.
You can combine the items emitted by multiple observables so that they act like a single sequence by using this operator.
The difference between the concat
operation
and merge
is that concat
cares about the ordering of sequences
(e.g. all items emitted by the first observable in the sequence
will come before the elements emitted by the second observable),
whereas merge
doesn't care about that (elements get
emitted as they come). Because of back-pressure applied to
observables, concat
is safe to use in all contexts, whereas
merge
requires buffering.
This version is reserving onError notifications until all of the observables complete and only then passing the issued errors(s) downstream. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
an observable that emits items that are the result of flattening the items emitted by the observables emitted by the source
Applies a function that you supply to each item emitted by the source observable, where that function returns observables, and then concatenating those resulting sequences and emitting the results of this concatenation.
Applies a function that you supply to each item emitted by the source observable, where that function returns observables, and then concatenating those resulting sequences and emitting the results of this concatenation.
The difference between the concat
operation
and merge
is that concat
cares about the ordering of sequences
(e.g. all items emitted by the first observable in the sequence
will come before the elements emitted by the second observable),
whereas merge
doesn't care about that (elements get
emitted as they come). Because of back-pressure applied to
observables, concat
is safe to use in all contexts, whereas
merge
requires buffering.
Applies a function that you supply to each item emitted by the source observable, where that function returns sequences and then concatenating those resulting sequences and emitting the results of this concatenation.
Applies a function that you supply to each item emitted by the source observable, where that function returns sequences and then concatenating those resulting sequences and emitting the results of this concatenation.
This version is reserving onError notifications until all of the observables complete and only then passing the issued errors(s) downstream. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
a function that, when applied to an item emitted by the source, returns an observable
an observable that emits items that are the result of flattening the items emitted by the observables emitted by the source
Creates a new Observable that emits the total number of onNext
events that were emitted by the source.
Creates a new Observable that emits the total number of onNext
events that were emitted by the source.
Note that this Observable emits only one item after the source is complete. And in case the source emits an error, then only that error will be emitted.
Only emit an item from an observable if a particular timespan has passed without it emitting another item.
Only emit an item from an observable if a particular timespan has passed without it emitting another item.
Note: If the source observable keeps emitting items more frequently than the length of the time window, then no items will be emitted by the resulting observable.
the length of the window of time that must pass after the emission of an item from the source observable in which that observable emits no items in order for the item to be emitted by the resulting observable
echoOnce for a similar operator that also mirrors the source observable
Emits the last item from the source Observable if a particular timespan has passed without it emitting another item, and keeps emitting that item at regular intervals until the source breaks the silence.
Emits the last item from the source Observable if a particular timespan has passed without it emitting another item, and keeps emitting that item at regular intervals until the source breaks the silence.
So compared to regular debounceTo this version keeps emitting the last item of the source.
Note: If the source Observable keeps emitting items more frequently than the length of the time window then no items will be emitted by the resulting Observable.
the length of the window of time that must pass after the emission of an item from the source Observable in which that Observable emits no items in order for the item to be emitted by the resulting Observable at regular intervals, also determined by period
echoRepeated for a similar operator that also mirrors the source observable
Doesn't emit anything until a timeout
period passes without the
source emitting anything.
Doesn't emit anything until a timeout
period passes without the
source emitting anything. When that timeout happens, we
subscribe to the observable generated by the given function, an
observable that will keep emitting until the source will break
the silence by emitting another event.
Note: If the source observable keeps emitting items more frequently than the length of the time window, then no items will be emitted by the resulting Observable.
the length of the window of time that must pass after the emission of an item from the source Observable in which that Observable emits no items in order for the item to be emitted by the resulting Observable
is a function that receives the last element generated by the source, generating an observable to be subscribed when the source is timing out
Emit items from the source, or emit a default item if the source completes after emitting no items.
Delays emitting the final onComplete
event by the specified amount.
Returns an Observable that emits the items emitted by the source Observable shifted forward in time by a specified delay.
Returns an Observable that emits the items emitted by the source Observable shifted forward in time by a specified delay.
Each time the source Observable emits an item, delay starts a timer, and when that timer reaches the given duration, the Observable returned from delay emits the same item.
NOTE: this delay refers strictly to the time between the
onNext
event coming from our source and the time it takes the
downstream observer to get this event. On the other hand the
operator is also applying back-pressure, so on slow observers
the actual time passing between two successive events may be
higher than the specified duration
.
- the delay to shift the source by
the source Observable shifted in time by the specified delay
Returns an Observable that emits the items emitted by the source Observable shifted forward in time.
Returns an Observable that emits the items emitted by the source Observable shifted forward in time.
This variant of delay
sets its delay duration on a per-item
basis by passing each item from the source Observable into a
function that returns an Observable and then monitoring those
Observables. When any such Observable emits an item or
completes, the Observable returned by delay emits the associated
item.
is a function that returns an Observable for
each item emitted by the source Observable, which is then
used to delay the emission of that item by the resulting
Observable until the Observable returned from selector
emits an item
the source Observable shifted in time by the specified delay
Hold an Observer's subscription request for a specified amount of time before passing it on to the source Observable.
Hold an Observer's subscription request for a specified amount of time before passing it on to the source Observable.
is the time to wait before the subscription is being initiated.
Hold an Observer's subscription request until the given trigger
observable either emits an item or completes, before passing it
on to the source Observable.
Hold an Observer's subscription request until the given trigger
observable either emits an item or completes, before passing it
on to the source Observable.
If the given trigger
completes in error, then the subscription is
terminated with onError
.
the observable that must either emit an item or complete in order for the source to be subscribed.
Converts the source Observable that emits Notification[A]
(the
result of materialize) back to an Observable that emits A
.
Suppress the duplicate elements emitted by the source Observable.
Suppress the duplicate elements emitted by the source Observable.
WARNING: this requires unbounded buffering.
Given a function that returns a key for each element emitted by the source Observable, suppress duplicates items.
Given a function that returns a key for each element emitted by the source Observable, suppress duplicates items.
WARNING: this requires unbounded buffering.
Suppress duplicate consecutive items emitted by the source Observable
Suppress duplicate consecutive items emitted by the source Observable
Executes the given callback when the stream has ended with an
onComplete
event, but before the complete event is emitted.
Executes the given callback when the stream has ended with an
onComplete
event, but before the complete event is emitted.
the callback to execute when the subscription is canceled
Executes the given callback when the streaming is stopped due to a downstream Stop signal returned by onNext.
Executes the given callback when the stream is interrupted with an
error, before the onError
event is emitted downstream.
Executes the given callback when the stream is interrupted with an
error, before the onError
event is emitted downstream.
NOTE: should protect the code in this callback, because if it
throws an exception the onError
event will prefer signaling
the original exception and otherwise the behavior is undefined.
Executes the given callback for each element generated by the source Observable, useful for doing side-effects.
Executes the given callback for each element generated by the source Observable, useful for doing side-effects.
a new Observable that executes the specified callback for each element
Executes the given callback only for the first element generated by the source Observable, useful for doing a piece of computation only when the stream starts.
Executes the given callback only for the first element generated by the source Observable, useful for doing a piece of computation only when the stream starts.
a new Observable that executes the specified callback only for the first element
Executes the given callback before the subscription happens.
Executes the given callback when the connection is being cancelled.
Executes the given callback when the stream has ended either with
an onComplete
or onError
event, or when the streaming stops by
a downstream Stop
being signaled.
Executes the given callback when the stream has ended either with
an onComplete
or onError
event, or when the streaming stops by
a downstream Stop
being signaled.
It is the equivalent of calling:
Drops the first n
elements (from the start).
Drops the first n
elements (from the start).
the number of elements to drop
a new Observable that drops the first n elements emitted by the source
Creates a new observable that drops the events of the source, only
for the specified timestamp
window.
Creates a new observable that drops the events of the source, only
for the specified timestamp
window.
the window of time during which the new observable must drop events emitted by the source
Drops the last n
elements (from the end).
Drops the last n
elements (from the end).
the number of elements to drop
a new Observable that drops the first n elements emitted by the source
Discard items emitted by the source until a second observable emits an item or completes.
Discard items emitted by the source until a second observable emits an item or completes.
If the trigger
observable completes in error, then the
resulting observable will also end in error when it notices
it (next time an element is emitted by the source).
the observable that has to emit an item before the source begin to be mirrored by the resulting observable
Drops the longest prefix of elements that satisfy the given predicate and returns a new observable that emits the rest.
Drops the longest prefix of elements that satisfy the given function and returns a new observable that emits the rest.
Drops the longest prefix of elements that satisfy the given function and returns a new observable that emits the rest. In comparison with dropWhile, this version accepts a function that takes an additional parameter: the zero-based index of the element.
Utility that can be used for debugging purposes.
Mirror the source observable as long as the source keeps emitting
items, otherwise if timeout
passes without the source emitting
anything new then the observable will emit the last item.
Mirror the source observable as long as the source keeps emitting
items, otherwise if timeout
passes without the source emitting
anything new then the observable will emit the last item.
This is the rough equivalent of:
Observable.merge(source, source.debounce(period))
Note: If the source Observable keeps emitting items more frequently than the length of the time window then the resulting observable will mirror the source exactly.
the window of silence that must pass in order for the observable to echo the last item
Mirror the source observable as long as the source keeps emitting
items, otherwise if timeout
passes without the source emitting
anything new then the observable will start emitting the last
item repeatedly.
Mirror the source observable as long as the source keeps emitting
items, otherwise if timeout
passes without the source emitting
anything new then the observable will start emitting the last
item repeatedly.
Note: If the source Observable keeps emitting items more frequently than the length of the time window then the resulting observable will mirror the source exactly.
the window of silence that must pass in order for the observable to start echoing the last item
Creates a new Observable that emits the events of the source and then it also emits the given elements (appended to the stream).
Emits the given exception instead of onComplete
.
Emits the given exception instead of onComplete
.
the exception to emit onComplete
a new Observable that emits an exception onComplete
Specify an override for the Scheduler that will be used for subscribing and for observing the source.
Specify an override for the Scheduler that will be used for subscribing and for observing the source.
Normally the Scheduler gets injected
implicitly when doing subscribe
, but this operator overrides
the injected subscriber for the given source. And if the source is
normally using that injected scheduler (given by subscribe
),
then the effect will be that all processing will now happen
on the override.
To put it in other words, in Monix it's usually the consumer and not the producer that specifies the scheduler and this operator allows for a different behavior.
This operator also includes the effects of subscribeOn, meaning that the subscription logic itself will start on the provided scheduler.
IMPORTANT: This operator is a replacement for the
observeOn operator
from ReactiveX, but does not work in the same way. The observeOn
operator forces the signaling to happen on a given Scheduler
, but
executeOn
is more relaxed, usage is not forced, the source just
gets injected with a different scheduler and it's up to the source
to actually use it. This also means the effects are more far reaching,
because the whole chain until the call of this operator is affected.
Alias for Observable.fork(fa, scheduler).
Mirrors the source observable, but upon subscription ensure that the evaluation forks into a separate (logical) thread.
Mirrors the source observable, but upon subscription ensure that the evaluation forks into a separate (logical) thread.
The execution is managed by the injected
scheduler in subscribe()
.
Alias for Observable.fork(fa).
Returns a new observable that will execute the source with a different ExecutionModel.
Returns a new observable that will execute the source with a different ExecutionModel.
This allows fine-tuning the options injected by the scheduler locally. Example:
observable.executeWithModel(AlwaysAsyncExecution)
is the ExecutionModel that will be used when evaluating the source.
Returns an Observable which emits a single value, either true, in case the given predicate holds for at least one item, or false otherwise.
Returns an Observable which emits a single value, either true, in case the given predicate holds for at least one item, or false otherwise.
is a function that evaluates the items emitted by the
source Observable, returning true
if they pass the
filter
an Observable that emits only true or false in case the given predicate holds or not for at least one item
Returns an observable that emits a single Throwable, in case an error was thrown by the source, otherwise it isn't going to emit anything.
Only emits those items for which the given predicate holds.
Only emits those items for which the given predicate holds.
a function that evaluates the items emitted by the source
returning true
if they pass the filter
a new observable that emits only those items in the source
for which the filter evaluates as true
Returns an Observable which only emits the first item for which the predicate holds.
Returns an Observable which only emits the first item for which the predicate holds.
is a function that evaluates the items emitted by the
source Observable, returning true
if they pass the filter
an Observable that emits only the first item in the original
Observable for which the filter evaluates as true
Emits the first element emitted by the source, or otherwise if the
source is completed without emitting anything, then the
default
is emitted.
Emits the first element emitted by the source, or otherwise if the
source is completed without emitting anything, then the
default
is emitted.
Alias for headOrElse
.
Applies a function that you supply to each item emitted by the source observable, where that function returns sequences that can be observed, and then concatenating those resulting sequences and emitting the results of this concatenation.
Applies a function that you supply to each item emitted by the source observable, where that function returns sequences that can be observed, and then concatenating those resulting sequences and emitting the results of this concatenation.
Alias for concatMap.
The difference between the concat
operation
and merge
is that concat
cares about the ordering of sequences
(e.g. all items emitted by the first observable in the sequence
will come before the elements emitted by the second observable),
whereas merge
doesn't care about that (elements get
emitted as they come). Because of back-pressure applied to
observables, concat
is safe to use in all contexts, whereas
merge
requires buffering.
Applies a function that you supply to each item emitted by the source observable, where that function returns sequences and then concatenating those resulting sequences and emitting the results of this concatenation.
Applies a function that you supply to each item emitted by the source observable, where that function returns sequences and then concatenating those resulting sequences and emitting the results of this concatenation.
It's an alias for concatMapDelayError.
a function that, when applied to an item emitted by the source Observable, returns an Observable
an Observable that emits the result of applying the transformation function to each item emitted by the source Observable and concatenating the results of the Observables obtained from this transformation.
An alias of switchMap.
An alias of switchMap.
Returns a new observable that emits the items emitted by the observable most recently generated by the mapping function.
Applies a binary operator to a start value and to elements produced by the source observable, going from left to right, producing and concatenating observables along the way.
Applies a binary operator to a start value and to elements produced by the source observable, going from left to right, producing and concatenating observables along the way.
Applies a binary operator to a start value and to elements produced by the source observable, going from left to right, producing and concatenating observables along the way.
This version of flatScan delays all errors until onComplete
,
when it will finally emit a CompositeException
.
It's the combination between scan and flatMapDelayError.
Concatenates the sequence of observables emitted by the source into one observable, without any transformation.
Concatenates the sequence of observables emitted by the source into one observable, without any transformation.
You can combine the items emitted by multiple observables so that they act like a single sequence by using this operator.
The difference between the concat
operation
and merge
is that concat
cares about the ordering of sequences
(e.g. all items emitted by the first observable in the sequence
will come before the elements emitted by the second observable),
whereas merge
doesn't care about that (elements get
emitted as they come). Because of back-pressure applied to
observables, concat
is safe to use in all contexts, whereas
merge
requires buffering.
Alias for concat.
an observable that emits items that are the result of flattening the items emitted by the observables emitted by the source
Alias for concatDelayError.
Alias for concatDelayError.
Concatenates the sequence of observables emitted by the source into one observable, without any transformation.
You can combine the items emitted by multiple observables so that they act like a single sequence by using this operator.
The difference between the concat
operation
and merge
is that concat
cares about the ordering of sequences
(e.g. all items emitted by the first observable in the sequence
will come before the elements emitted by the second observable),
whereas merge
doesn't care about that (elements get
emitted as they come). Because of back-pressure applied to
observables, concat
is safe to use in all contexts, whereas
merge
requires buffering.
This version is reserving onError
notifications until all of the observables complete and only
then passing the issued errors(s) downstream. Note that
the streamed error is a
CompositeException,
since multiple errors from multiple streams can happen.
an observable that emits items that are the result of flattening the items emitted by the observables emitted by the source
Alias for switch
Alias for switch
Convert an observable that emits observables into a single observable that emits the items emitted by the most-recently-emitted of those observables.
Applies a binary operator to a start value and all elements of
this Observable, going left to right and returns a new
Observable that emits only one item before onComplete
.
Applies a binary operator to a start value and all elements of
this Observable, going left to right and returns a new
Observable that emits only one item before onComplete
.
is the initial state, specified as a possibly lazy value; it gets evaluated when the subscription happens and if it triggers an error then the subscriber will get immediately terminated with an error
is an operator that will fold the signals of the source observable, returning the next state
Folds the source observable, from start to finish, until the
source completes, or until the operator short-circuits the
process by returning false
.
Folds the source observable, from start to finish, until the
source completes, or until the operator short-circuits the
process by returning false
.
Note that a call to foldLeftF is equivalent to this function
being called with an operator always returning true
as the first
member of its result.
is the initial state, specified as a possibly lazy value; it gets evaluated when the subscription happens and if it triggers an error then the subscriber will get immediately terminated with an error
is an operator that will fold the signals of the source observable, returning either a new state along with a boolean that should become false in case the folding must be interrupted.
Returns an Observable that emits a single boolean, either true, in case the given predicate holds for all the items emitted by the source, or false in case at least one item is not verifying the given predicate.
Returns an Observable that emits a single boolean, either true, in case the given predicate holds for all the items emitted by the source, or false in case at least one item is not verifying the given predicate.
is a function that evaluates the items emitted by the source
Observable, returning true
if they pass the filter
an Observable that emits only true or false in case the given predicate holds or not for all the items
Groups the items emitted by an Observable according to a specified criterion, and emits these grouped items as GroupedObservables, one GroupedObservable per group.
Groups the items emitted by an Observable according to a specified criterion, and emits these grouped items as GroupedObservables, one GroupedObservable per group.
Note: A GroupedObservable
will cache the items it is to emit until such time as it is
subscribed to. For this reason, in order to avoid memory leaks,
you should not simply ignore those GroupedObservables that do
not concern you. Instead, you can signal to them that they may
discard their buffers by doing something like source.take(0)
.
a function that extracts the key for each item
Only emits the first element emitted by the source observable, after which it's completed immediately.
Emits the first element emitted by the source, or otherwise if the
source is completed without emitting anything, then the
default
is emitted.
Alias for completed.
Alias for completed. Ignores all items emitted by the source and only calls onCompleted or onError.
an empty sequence that only calls onCompleted or onError, based on which one is called by the source Observable
Creates a new observable from this observable and another given observable by interleaving their items into a strictly alternating sequence.
Creates a new observable from this observable and another given observable by interleaving their items into a strictly alternating sequence.
So the first item emitted by the new observable will be the item
emitted by self
, the second item will be emitted by the other
observable, and so forth; when either self
or other
calls
onCompletes
, the items will then be directly coming from the
observable that has not completed; when onError
is called by
either self
or other
, the new observable will call onError
and halt.
See merge for a more relaxed alternative that doesn't emit items in strict alternating sequence.
is an observable that interleaves with the source
a new observable sequence that alternates emission of the items from both child streams
Returns an Observable that emits true if the source Observable is empty, otherwise false.
Only emits the last element emitted by the source observable, after which it's completed immediately.
Returns a new observable that applies the given function to each item emitted by the source and emits the result.
Given a mapping function that maps events to tasks,
applies it in parallel on the source, but with a specified
parallelism
, which indicates the maximum number of tasks that
can be executed in parallel.
Given a mapping function that maps events to tasks,
applies it in parallel on the source, but with a specified
parallelism
, which indicates the maximum number of tasks that
can be executed in parallel.
Similar in spirit with Consumer.loadBalance, but expressed as an operator that executes Task instances in parallel.
Note that when the specified parallelism
is 1, it has the same
behavior as mapTask.
is the maximum number of tasks that can be executed in parallel, over which the source starts being back-pressured
is the mapping function that produces tasks to execute in parallel, which will eventually produce events for the resulting observable stream
mapTask for serial execution
Alias for mapTask.
Maps elements from the source using a function that can do
asynchronous processing by means of scala.concurrent.Future
.
Maps elements from the source using a function that can do
asynchronous processing by means of scala.concurrent.Future
.
Given a source observable, this function is basically the equivalent of doing:
observable.concatMap(a => Observable.fromFuture(f(a)))
However prefer this operator to concatMap
because it
is more clear and has better performance.
mapTask for the version that can work with Task
Maps elements from the source using a function that can do asynchronous processing by means of Task.
Maps elements from the source using a function that can do asynchronous processing by means of Task.
Given a source observable, this function is basically the equivalent of doing:
observable.concatMap(a => Observable.fromTask(f(a)))
However prefer this operator to concatMap
because it
is more clear and has better performance.
mapFuture for the version that can work with
scala.concurrent.Future
Converts the source Observable that emits A
into an Observable
that emits Notification[A]
.
Takes the elements of the source Observable and emits the element
that has the maximum key value, where the key is generated by
the given function f
.
Takes the elements of the source Observable and emits the maximum value, after the source has completed.
Merges the sequence of Observables emitted by the source into one Observable, without any transformation.
Merges the sequence of Observables emitted by the source into one Observable, without any transformation.
You can combine the items emitted by multiple Observables so that they act like a single Observable by using this operator.
an Observable that emits items that are the
result of flattening the items emitted by the Observables
emitted by this
.
this operation needs to do buffering and by not specifying an OverflowStrategy, the default strategy is being used.
Merges the sequence of Observables emitted by the source into one Observable, without any transformation.
Merges the sequence of Observables emitted by the source into one Observable, without any transformation.
You can combine the items emitted by multiple Observables so that they act like a single Observable by using this operator.
This version is reserving onError notifications until all of the observables complete and only then passing the issued errors(s) downstream. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
an Observable that emits items that are the
result of flattening the items emitted by the Observables
emitted by this
.
this operation needs to do buffering and by not specifying an OverflowStrategy, the default strategy is being used.
Creates a new observable by applying a function that you supply to each item emitted by the source observable, where that function returns an observable, and then merging those resulting observable and emitting the results of this merger.
Creates a new observable by applying a function that you supply to each item emitted by the source observable, where that function returns an observable, and then merging those resulting observable and emitting the results of this merger.
The difference between this and concatMap
is that
concatMap
cares about ordering of emitted
items (e.g. all items emitted by the first observable in
the sequence will come before the elements emitted by the
second observable), whereas merge
doesn't care about
that (elements get emitted as they come). Because of
back-pressure applied to observables, the concat
operation
is safe to use in all contexts, whereas merge
requires
buffering.
- the transformation function
an observable that emits the result of applying the transformation function to each item emitted by the source observable and merging the results of the observables obtained from this transformation.
Creates a new observable by applying a function that you supply to each item emitted by the source observable, where that function returns an observable, and then merging those resulting observable and emitting the results of this merger.
Creates a new observable by applying a function that you supply to each item emitted by the source observable, where that function returns an observable, and then merging those resulting observable and emitting the results of this merger.
The difference between this and concatMap
is that
concatMap
cares about ordering of emitted
items (e.g. all items emitted by the first observable in
the sequence will come before the elements emitted by the
second observable), whereas merge
doesn't care about
that (elements get emitted as they come). Because of
back-pressure applied to observables, the concat
operation
is safe to use in all contexts, whereas merge
requires
buffering.
This version is reserving onError notifications until all of the observables complete and only then passing the issued errors(s) downstream. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
- the transformation function
an observable that emits the result of applying the transformation function to each item emitted by the source observable and merging the results of the observables obtained from this transformation.
Takes the elements of the source Observable and emits the element
that has the minimum key value, where the key is generated by
the given function f
.
Takes the elements of the source Observable and emits the minimum value, after the source has completed.
Returns an Observable that emits false if the source Observable is empty, otherwise true.
If the connection is cancelled
then trigger a CancellationException
.
If the connection is cancelled
then trigger a CancellationException
.
A connection can be cancelled with the help of the Cancelable returned on subscribe.
Because the cancellation is effectively concurrent with the signals the Observer receives and because we need to uphold the contract, this operator will effectively synchronize access to onNext, onComplete and onError. It will also watch out for asynchronous Stop events.
In other words, this operator does heavy synchronization, can prove to be inefficient and you should avoid using it because the signaled error can interfere with functionality from other operators that use cancelation internally and cancellation in general is a side-effecting operation that should be avoided, unless it's necessary.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
the streaming of events continues with the specified backup
sequence.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
the streaming of events continues with the specified backup
sequence.
The created Observable mirrors the behavior of the source in case the source does not end with an error.
NOTE that compared with onErrorResumeNext
from Rx.NET, the
streaming is not resumed in case the source is terminated
normally with an onComplete
.
is a backup sequence that's being subscribed in case the source terminates with an error.
Returns an observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which
case the streaming of events fallbacks to an observable
emitting a single element generated by the backup function.
Returns an observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which
case the streaming of events fallbacks to an observable
emitting a single element generated by the backup function.
See onErrorRecover for the version that takes a partial function as a parameter.
- a function that matches errors with a backup element that is emitted when the source throws an error.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
the streaming of events continues with the specified backup
sequence generated by the given function.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
the streaming of events continues with the specified backup
sequence generated by the given function.
See onErrorRecoverWith for the version that takes a partial function as a parameter.
is a function that matches errors with a backup throwable that is subscribed when the source throws an error.
Returns an observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which
case the streaming of events fallbacks to an observable
emitting a single element generated by the backup function.
Returns an observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which
case the streaming of events fallbacks to an observable
emitting a single element generated by the backup function.
The created Observable mirrors the behavior of the source
in case the source does not end with an error or if the
thrown Throwable
is not matched.
See onErrorHandle for the version that takes a total function as a parameter.
- a function that matches errors with a backup element that is emitted when the source throws an error.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
the streaming of events continues with the specified backup
sequence generated by the given function.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
the streaming of events continues with the specified backup
sequence generated by the given function.
The created Observable mirrors the behavior of the source in
case the source does not end with an error or if the thrown
Throwable
is not matched.
See onErrorHandleWith for the version that takes a total function as a parameter.
is a function that matches errors with a backup throwable that is subscribed when the source throws an error.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
it tries subscribing to the source again in the hope that it
will complete without an error.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
it tries subscribing to the source again in the hope that it
will complete without an error.
The number of retries is limited by the specified maxRetries
parameter, so for an Observable that always ends in error the
total number of subscriptions that will eventually happen is
maxRetries + 1
.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
it tries subscribing to the source again in the hope that it
will complete without an error.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
it tries subscribing to the source again in the hope that it
will complete without an error.
The given predicate establishes if the subscription should be retried or not.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
it tries subscribing to the source again in the hope that it
will complete without an error.
Returns an Observable that mirrors the behavior of the source,
unless the source is terminated with an onError
, in which case
it tries subscribing to the source again in the hope that it
will complete without an error.
NOTE: The number of retries is unlimited, so something like
Observable.error(new RuntimeException).onErrorRestartUnlimited
will loop forever.
Given a Pipe, transform the source observable with it.
Applies a binary operator to a start value and all elements of
this Observable, going left to right and returns a new
Observable that emits only one item before onComplete
.
Repeats the items emitted by the source continuously.
Repeats the items emitted by the source continuously. It
caches the generated items until onComplete
and repeats them
forever.
It terminates either on error or if the source is empty.
Keeps restarting / resubscribing the source until the predicate
returns true
for the the first emitted element, after which
it starts mirroring the source.
Emit the most recent items emitted by the source within periodic time intervals.
Emit the most recent items emitted by the source within periodic time intervals.
Use the sample
operator to periodically look at an observable
to see what item it has most recently emitted since the previous
sampling. Note that if the source observable has emitted no
items since the last time it was sampled, the observable that
results from the sample
operator will emit no item for that
sampling period.
the timespan at which sampling occurs
sampleRepeated for repeating the last value on silence
sampleBy for fine control
Returns an observable that, when the specified sampler emits an item or completes, emits the most recently emitted item (if any) emitted by the source since the previous emission from the sampler.
Returns an observable that, when the specified sampler emits an item or completes, emits the most recently emitted item (if any) emitted by the source since the previous emission from the sampler.
Use the sampleBy
operator to periodically look at an observable
to see what item it has most recently emitted since the previous
sampling. Note that if the source observable has emitted no
items since the last time it was sampled, the observable that
results from the sampleBy
operator will emit no item.
- the observable to use for sampling the source
sampleRepeatedBy for repeating the last value on silence
sample for periodic sampling
Emit the most recent items emitted by an observable within periodic time intervals.
Emit the most recent items emitted by an observable within periodic time intervals. If no new value has been emitted since the last time it was sampled, it signals the last emitted value anyway.
the timespan at which sampling occurs
sampleRepeatedBy for fine control
sample for a variant that doesn't repeat the last value on silence
Returns an observable that, when the specified sampler observable emits an item or completes, emits the most recently emitted item (if any) emitted by the source Observable since the previous emission from the sampler observable.
Returns an observable that, when the specified sampler observable emits an item or completes, emits the most recently emitted item (if any) emitted by the source Observable since the previous emission from the sampler observable. If no new value has been emitted since the last time it was sampled, it signals the last emitted value anyway.
- the Observable to use for sampling the source Observable
sampleRepeated for a periodic sampling
sampleBy for a variant that doesn't repeat the last value on silence
Applies a binary operator to a start value and all elements of this Observable, going left to right and returns a new Observable that emits on each step the result of the applied function.
Applies a binary operator to a start value and all elements of this Observable, going left to right and returns a new Observable that emits on each step the result of the applied function.
Similar to foldLeftF, but emits the state on each step. Useful for modeling finite state machines.
Creates a new Observable that emits the given elements and then it also emits the events of the source (prepend operation).
Returns a new Observable that uses the specified Scheduler
for
initiating the subscription.
Given a source that emits numeric values, the sum
operator sums
up all values and at onComplete it emits the total.
Convert an observable that emits observables into a single observable that emits the items emitted by the most-recently-emitted of those observables.
In case the source is empty, switch to the given backup.
Returns a new observable that emits the items emitted by the observable most recently generated by the mapping function.
Drops the first element of the source observable, emitting the rest.
Selects the first n
elements (from the start).
Selects the first n
elements (from the start).
the number of elements to take
a new Observable that emits only the first
n
elements from the source
Creates a new Observable that emits the events of the source, only
for the specified timestamp
, after which it completes.
Creates a new Observable that emits the events of the source, only
for the specified timestamp
, after which it completes.
the window of time during which the new Observable is allowed to emit the events of the source
Creates a new observable that only emits the last n
elements
emitted by the source.
Creates a new observable that only emits the last n
elements
emitted by the source.
In case the source triggers an error, then the underlying buffer gets dropped and the error gets emitted immediately.
Creates a new observable that mirrors the source until
the given trigger
emits either an element or onComplete
,
after which it is completed.
Creates a new observable that mirrors the source until
the given trigger
emits either an element or onComplete
,
after which it is completed.
The resulting observable is completed as soon as trigger
emits either an onNext
or onComplete
. If trigger
emits an onError
, then the resulting observable is also
completed with error.
is an observable that will cancel the streaming as soon as it emits an event
Takes longest prefix of elements that satisfy the given predicate and returns a new Observable that emits those elements.
Takes longest prefix of elements that satisfy the given predicate and returns a new Observable that emits those elements.
Returns an Observable that emits only the first item emitted by the source Observable during sequential time windows of a specified duration.
Returns an Observable that emits only the first item emitted by the source Observable during sequential time windows of a specified duration.
This differs from Observable!.throttleLast in that this only
tracks passage of time whereas throttleLast
ticks at scheduled
intervals.
time to wait before emitting another item after emitting the last item
Emit the most recent items emitted by the source within periodic time intervals.
Emit the most recent items emitted by the source within periodic time intervals.
Alias for sample.
duration of windows within which the last item emitted by the source Observable will be emitted
Only emit an item from an observable if a particular timespan has passed without it emitting another item.
Only emit an item from an observable if a particular timespan has passed without it emitting another item.
Note: If the source observable keeps emitting items more frequently than the length of the time window, then no items will be emitted by the resulting observable.
Alias for debounce.
the length of the window of time that must pass after the emission of an item from the source observable in which that observable emits no items in order for the item to be emitted by the resulting observable
echoOnce for a similar operator that also mirrors the source observable
Returns an observable that mirrors the source but that will trigger a
DownstreamTimeoutException
in case the downstream subscriber takes more than the given timespan
to process an onNext
message.
Returns an observable that mirrors the source but that will trigger a
DownstreamTimeoutException
in case the downstream subscriber takes more than the given timespan
to process an onNext
message.
Note that this ignores the time it takes for the upstream to send
onNext
messages. For detecting slow producers see timeoutOnSlowUpstream.
maximum duration for onNext
.
Returns an observable that mirrors the source but applies a timeout for each emitted item by the upstream.
Returns an observable that mirrors the source but applies a timeout for each emitted item by the upstream. If the next item isn't emitted within the specified timeout duration starting from its predecessor, the resulting Observable terminates and notifies observers of a TimeoutException.
Note that this ignores the time it takes to process onNext
.
If dealing with a slow consumer, see timeoutOnSlowDownstream.
maximum duration between emitted items before
a timeout occurs (ignoring the time it takes to process onNext
)
Returns an observable that mirrors the source but applies a timeout for each emitted item by the upstream.
Returns an observable that mirrors the source but applies a timeout for each emitted item by the upstream. If the next item isn't emitted within the specified timeout duration starting from its predecessor, the source is terminated and the downstream gets subscribed to the given backup.
Note that this ignores the time it takes to process onNext
.
If dealing with a slow consumer, see timeoutOnSlowDownstream.
maximum duration between emitted items before
a timeout occurs (ignoring the time it takes to process onNext
)
is the alternative data source to subscribe to on timeout
While the destination observer is busy, buffers events, applying the given overflowStrategy.
While the destination observer is busy, buffers events, applying the given overflowStrategy.
- the overflow strategy used for buffering, which specifies what to do in case we're dealing with a slow consumer - should an unbounded buffer be used, should back-pressure be applied, should the pipeline drop newer or older events, should it drop the whole buffer? See OverflowStrategy for more details.
While the destination observer is busy, drop the incoming events.
While the destination observer is busy, drop the incoming events.
While the destination observer is busy, drop the incoming events. When the downstream recovers, we can signal a special event meant to inform the downstream observer how many events where dropped.
- a function that is used for signaling a special event used to inform the consumers that an overflow event happened, function that receives the number of dropped events as a parameter (see OverflowStrategy.Evicted)
Combines the elements emitted by the source with the latest element emitted by another observable.
Combines the elements emitted by the source with the latest element emitted by another observable.
Similar with combineLatest
, but only emits items when the single source
emits an item (not when any of the Observables that are passed to the operator
do, as combineLatest does).
is an observable that gets paired with the source
is a mapping function over the generated pairs
Combines the elements emitted by the source with the latest elements emitted by two observables.
Combines the elements emitted by the source with the latest elements emitted by two observables.
Similar with combineLatest
, but only emits items when the single source
emits an item (not when any of the Observables that are passed to the operator
do, as combineLatest does).
is the first observable that gets paired with the source
is the second observable that gets paired with the source
is a mapping function over the generated pairs
Combines the elements emitted by the source with the latest elements emitted by three observables.
Combines the elements emitted by the source with the latest elements emitted by three observables.
Similar with combineLatest
, but only emits items when the single source
emits an item (not when any of the Observables that are passed to the operator
do, as combineLatest does).
is the first observable that gets paired with the source
is the second observable that gets paired with the source
is the third observable that gets paired with the source
is a mapping function over the generated pairs
Combines the elements emitted by the source with the latest elements emitted by four observables.
Combines the elements emitted by the source with the latest elements emitted by four observables.
Similar with combineLatest
, but only emits items when the single source
emits an item (not when any of the Observables that are passed to the operator
do, as combineLatest does).
is the first observable that gets paired with the source
is the second observable that gets paired with the source
is the third observable that gets paired with the source
is the fourth observable that gets paired with the source
is a mapping function over the generated pairs
Combines the elements emitted by the source with the latest elements emitted by five observables.
Combines the elements emitted by the source with the latest elements emitted by five observables.
Similar with combineLatest
, but only emits items when the single source
emits an item (not when any of the Observables that are passed to the operator
do, as combineLatest does).
is the first observable that gets paired with the source
is the second observable that gets paired with the source
is the third observable that gets paired with the source
is the fourth observable that gets paired with the source
is the fifth observable that gets paired with the source
is a mapping function over the generated pairs
Combines the elements emitted by the source with the latest elements emitted by six observables.
Combines the elements emitted by the source with the latest elements emitted by six observables.
Similar with combineLatest
, but only emits items when the single source
emits an item (not when any of the Observables that are passed to the operator
do, as combineLatest does).
is the first observable that gets paired with the source
is the second observable that gets paired with the source
is the third observable that gets paired with the source
is the fourth observable that gets paired with the source
is the fifth observable that gets paired with the source
is the sixth observable that gets paired with the source
is a mapping function over the generated pairs
Creates a new observable from this observable and another given observable by combining their items in pairs in a strict sequence.
Creates a new observable from this observable and another given observable by combining their items in pairs in a strict sequence.
So the first item emitted by the new observable will be the tuple of the first items emitted by each of the source observables; the second item emitted by the new observable will be a tuple with the second items emitted by each of those observables; and so forth.
See combineLatest for a more relaxed alternative that doesn't combine items in strict sequence.
is an observable that gets paired with the source
a new observable sequence that emits the paired items of the source observables
Creates a new observable from this observable and another given observable by combining their items in pairs in a strict sequence.
Creates a new observable from this observable and another given observable by combining their items in pairs in a strict sequence.
So the first item emitted by the new observable will be the result of the function applied to the first item emitted by each of the source observables; the second item emitted by the new observable will be the result of the function applied to the second item emitted by each of those observables; and so forth.
See combineLatestMap for a more relaxed alternative that doesn't combine items in strict sequence.
is an observable that gets paired with the source
is a mapping function over the generated pairs
Zips the emitted elements of the source with their indices.
Defines the available operations for observable-like instances.