Observable

Abstract Value Members

abstract def onSubscribe(subscriber: Subscriber[T]): Unit

Characteristic function for an Observable instance, that creates the subscription and that eventually starts the streaming of events to the given Observer, being meant to be overridden in custom combinators or in classes implementing Observable.
Characteristic function for an Observable instance, that creates the subscription and that eventually starts the streaming of events to the given Observer, being meant to be overridden in custom combinators or in classes implementing Observable.
This function is "unsafe" to call because it does not protect the calls to the given Observer implementation in regards to unexpected exceptions that violate the contract, therefore the given instance must respect its contract and not throw any exceptions when the observable calls onNext, onComplete and onError. If it does, then the behavior is undefined.

See also
subscribe.

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
def ++[U >: T](other: ⇒ Observable[U]): Observable[U]

Concatenates the source Observable with the other Observable, as specified.
Concatenates the source Observable with the other Observable, as specified.
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.
Example:
1. val concat = Observable(1,2,3) ++ Observable(4,5) concat.dump("O").subscribe() // 0: O-->1 // 1: O-->2 // 2: O-->3 // 3: O-->4 // 4: O-->5 // 5: O completed
def +:[U >: T](elem: U): Observable[U]

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 given element and then it also emits the events of the source (prepend operation).
Example:
1. val source = 1 +: Observable(2, 3, 4) source.dump("O").subscribe() // 0: O-->1 // 1: O-->2 // 2: O-->3 // 3: O-->4 // 4: O completed
def :+[U >: T](elem: U): Observable[U]

Creates a new Observable that emits the events of the source and then it also emits the given element (appended to the stream).
Creates a new Observable that emits the events of the source and then it also emits the given element (appended to the stream).
Example:
1. val source = Observable(1, 2, 3) :+ 4 source.dump("O").subscribe() // 0: O-->1 // 1: O-->2 // 2: O-->3 // 3: O-->4 // 4: O completed
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def ambWith[U >: T](other: Observable[U]): Observable[U]

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.
def asFuture(implicit s: Scheduler): Future[Option[T]]

Returns the first generated result as a Future and then cancels the subscription.
final def asInstanceOf[T0]: T0

Definition Classes
Any
def asyncBoundary[U >: T](overflowStrategy: Evicted, onOverflow: (Long) ⇒ U): Observable[U]

Forces a buffered asynchronous boundary.
Forces a buffered asynchronous boundary.
Internally it wraps the observer implementation given to onSubscribe into a BufferedSubscriber.
Normally Monifu'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.
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
onOverflow
- 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)
def asyncBoundary(overflowStrategy: OverflowStrategy): Observable[T]

Forces a buffered asynchronous boundary.
Forces a buffered asynchronous boundary.
Internally it wraps the observer implementation given to onSubscribe into a BufferedSubscriber.
Normally Monifu'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.
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
def behavior[U >: T](initialValue: U)(implicit s: Scheduler): ConnectableObservable[U]

Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e.
Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e. whose source is shared by all observers). The underlying subject used is a BehaviorSubject.
def buffer(timespan: FiniteDuration, maxSize: Int): Observable[Seq[T]]

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 maxSize argument (whichever is reached first). When the source Observable completes or encounters an error, the resulting Observable emits the current buffer and propagates the notification from the source Observable.
timespan
the interval of time at which it should emit the buffered bundle
maxSize
is the maximum bundle size
def buffer(timespan: FiniteDuration): Observable[Seq[T]]

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.
timespan
the interval of time at which it should emit the buffered bundle
def buffer(count: Int, skip: Int): Observable[Seq[T]]

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. When the source Observable completes or encounters an error, the resulting Observable emits the current buffer and propagates the notification from the source Observable.
There are 3 possibilities:
1. in case skip == count, then there are no items dropped and no overlap, the call being equivalent to window(count) 2. in case skip < count, then overlap between windows happens, with the number of elements being repeated being count - skip 3. in case skip > count, then skip - count elements start getting dropped between windows
count
the maximum size of each buffer before it should be emitted
skip
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)
def buffer(count: Int): Observable[Seq[T]]

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 the reached the given count.
count
the maximum size of each buffer before it should be emitted
def bufferIntrospective(maxSize: Int): Observable[List[T]]

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.
def cache(maxCapacity: Int): Observable[T]

Caches the emissions from the source Observable and replays them in order to any subsequent Subscribers.
Caches the emissions from the source Observable and replays them in order to any subsequent Subscribers. This method has similar behavior to replay except that this auto-subscribes to the source Observable rather than returning a ConnectableObservable for which you must call connect to activate the subscription.
When you call cache, it does not yet subscribe to the source Observable and so does not yet begin caching items. This only happens when the first Subscriber calls the resulting Observable's subscribe method.
maxCapacity
is the maximum buffer size after which old events start being dropped (according to what happens when using ReplaySubject.createWithSize)
returns
an Observable that, when first subscribed to, caches all of its items and notifications for the benefit of subsequent subscribers
def cache: Observable[T]

Caches the emissions from the source Observable and replays them in order to any subsequent Subscribers.
Caches the emissions from the source Observable and replays them in order to any subsequent Subscribers. This method has similar behavior to replay except that this auto-subscribes to the source Observable rather than returning a ConnectableObservable for which you must call connect to activate the subscription.
When you call cache, it does not yet subscribe to the source Observable and so does not yet begin caching items. This only happens when the first Subscriber calls the resulting Observable's subscribe method.
Note: You sacrifice the ability to cancel the origin when you use the cache operator so be careful not to use this on Observables that emit an infinite or very large number of items that will use up memory.
returns
an Observable that, when first subscribed to, caches all of its items and notifications for the benefit of subsequent subscribers
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def collect[U](pf: PartialFunction[T, U]): Observable[U]

Returns an Observable by applying the given partial function to the source observable for each element for which the given partial function is defined.
Returns an Observable by applying the given partial function to the source observable for each element for which the given partial function is defined.
Useful to be used instead of a filter & map combination.
pf
the function that filters and maps the resulting observable
returns
an Observable that emits the transformed items by the given partial function
def combineLatest[U](other: Observable[U]): Observable[(T, U)]

Creates a new Observable from this Observable and another given Observable.
Creates a new Observable from this Observable and another given Observable.
This operator behaves in a similar way to zip, but while zip emits items only when all of the zipped source Observables have emitted a previously unzipped item, combine emits an item whenever any of the source Observables emits an item (so long as each of the source Observables has emitted at least one item).
def combineLatestDelayError[U](other: Observable[U]): Observable[(T, U)]

Creates a new Observable from this Observable and another given Observable.
Creates a new Observable from this Observable and another given Observable.
This operator behaves in a similar way to zip, but while zip emits items only when all of the zipped source Observables have emitted a previously unzipped item, combine emits an item whenever any of the source Observables emits an item (so long as each of the source Observables has emitted at least one item).
This version of combineLatest is reserving onError notifications until all of the combined Observables complete and only then passing it along to the observers.

See also
Observable!.combineLatest
def complete: Observable[Nothing]

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.
returns
an empty Observable that only calls onCompleted or onError, based on which one is called by the source Observable
def concat[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

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 Observable by using this method.
The difference between the concat operation and merge is that concat 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, Observable!.concat is safe to use in all contexts, whereas merge requires buffering.
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def concatDelayError[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

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 Observable by using this method.
The difference between the concat operation and merge is that concat 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, Observable!.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) along to the observers. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def concatMap[U](f: (T) ⇒ Observable[U]): Observable[U]

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 concatenating those resulting Observables and emitting the results of this concatenation.
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 concatenating those resulting Observables and emitting the results of this concatenation.
f
a function that, when applied to an item emitted by the source Observable, returns an Observable
returns
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.
def concatMapDelayError[U](f: (T) ⇒ Observable[U]): Observable[U]

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 concatenating those resulting Observables and emitting the results of this concatenation.
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 concatenating those resulting Observables and emitting the results of this concatenation.
It's like Observable!.concatMap, except that the created observable is reserving onError notifications until all of the merged Observables complete and only then passing it along to the observers.
f
a function that, when applied to an item emitted by the source Observable, returns an Observable
returns
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.
def count: Observable[Long]

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.
def debounce[U](selector: (T) ⇒ Observable[Any], f: (T) ⇒ Observable[U]): Observable[U]

Only emit an item from an Observable if a particular timespan has passed without it emitting another item, a timespan indicated by the completion of an observable generated the selector function.
Only emit an item from an Observable if a particular timespan has passed without it emitting another item, a timespan indicated by the completion of an observable generated the selector function.
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.
selector
function to retrieve a sequence that indicates the throttle duration for each item
f
is a function that receives the last element generated by the source, generating an observable to be subscribed when the source is timing out
def debounce(selector: (T) ⇒ Observable[Any]): Observable[T]

Only emit an item from an Observable if a particular timespan has passed without it emitting another item, a timespan indicated by the completion of an observable generated the selector function.
Only emit an item from an Observable if a particular timespan has passed without it emitting another item, a timespan indicated by the completion of an observable generated the selector function.
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.
selector
function to retrieve a sequence that indicates the throttle duration for each item
def debounce[U](timeout: FiniteDuration, f: (T) ⇒ Observable[U]): Observable[U]

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.
timeout
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
f
is a function that receives the last element generated by the source, generating an observable to be subscribed when the source is timing out
def debounce(timeout: FiniteDuration): Observable[T]

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.
timeout
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

See also
echoOnce for a similar operator that also mirrors the source observable
def debounceRepeated(period: FiniteDuration): Observable[T]

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 debounce it 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.
period
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

See also
echoRepeated for a similar operator that also mirrors the source observable
def defaultIfEmpty[U >: T](default: U): Observable[U]

Emit items from the source Observable, or emit a default item if the source Observable completes after emitting no items.
def delay[U](selector: (T) ⇒ Observable[U]): Observable[T]

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.
selector
- 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
returns
the source Observable shifted in time by the specified delay

See also
delay(duration) for the other variant
def delay(duration: FiniteDuration): Observable[T]

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.
duration
- the delay to shift the source by
returns
the source Observable shifted in time by the specified delay
def delaySubscription(timespan: FiniteDuration): Observable[T]

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.
timespan
is the time to wait before the subscription is being initiated.
def delaySubscription[U](trigger: Observable[U]): Observable[T]

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.
trigger
- the observable that must either emit an item or complete in order for the source to be subscribed.
def distinct[U](fn: (T) ⇒ U): Observable[T]

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.
def distinct: Observable[T]

Suppress the duplicate elements emitted by the source Observable.
Suppress the duplicate elements emitted by the source Observable.
WARNING: this requires unbounded buffering.
def distinctUntilChanged[U](fn: (T) ⇒ U): Observable[T]

Suppress duplicate consecutive items emitted by the source Observable
def distinctUntilChanged: Observable[T]

Suppress duplicate consecutive items emitted by the source Observable
def doOnCanceled(cb: ⇒ Unit): Observable[T]

Executes the given callback if the downstream observer has canceled the streaming.
def doOnComplete(cb: ⇒ Unit): Observable[T]

Executes the given callback when the stream has ended, but before the complete event is emitted.
Executes the given callback when the stream has ended, but before the complete event is emitted.
cb
the callback to execute when the subscription is canceled
def doOnError(cb: (Throwable) ⇒ Unit): Observable[T]

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.
def doOnStart(cb: (T) ⇒ Unit): Observable[T]

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 started.
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 started.
returns
a new Observable that executes the specified callback only for the first element
def doWork(cb: (T) ⇒ Unit): Observable[T]

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.
returns
a new Observable that executes the specified callback for each element
def drop(n: Int): Observable[T]

Drops the first n elements (from the start).
Drops the first n elements (from the start).
n
the number of elements to drop
returns
a new Observable that drops the first n elements emitted by the source
def dropByTimespan(timespan: FiniteDuration): Observable[T]

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.
timespan
the window of time during which the new Observable is must drop the events emitted by the source
def dropWhile(p: (T) ⇒ Boolean): Observable[T]

Drops the longest prefix of elements that satisfy the given predicate and returns a new Observable that emits the rest.
def dropWhileWithIndex(p: (T, Int) ⇒ Boolean): Observable[T]

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.
def dump(prefix: String, out: PrintStream = System.out): Observable[T]

Utility that can be used for debugging purposes.
def echoOnce(timeout: FiniteDuration): Observable[T]

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.
timeout
the window of silence that must pass in order for the observable to echo the last item
def echoRepeated(timeout: FiniteDuration): Observable[T]

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.
This is the rough equivalent of:
```
source.switch { e =>
  e +: Observable.intervalWithFixedDelay(delay, delay)
}
```
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.
timeout
the window of silence that must pass in order for the observable to start echoing the last item
def endWith[U >: T](elems: U*): Observable[U]

Creates a new Observable that emits the events of the source and then it also emits the given elements (appended to the stream).
def endWithError(error: Throwable): Observable[T]

Emits the given exception instead of onComplete.
Emits the given exception instead of onComplete.
error
the exception to emit onComplete
returns
a new Observable that emits an exception onComplete
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def error: Observable[Throwable]

Returns an Observable that emits a single Throwable, in case an error was thrown by the source Observable, otherwise it isn't going to emit anything.
def exists(p: (T) ⇒ Boolean): Observable[Boolean]

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.
p
a function that evaluates the items emitted by the source Observable, returning true if they pass the filter
returns
an Observable that emits only true or false in case the given predicate holds or not for at least one item
def filter(p: (T) ⇒ Boolean): Observable[T]

Returns an Observable which only emits those items for which the given predicate holds.
Returns an Observable which only emits those items for which the given predicate holds.
p
a function that evaluates the items emitted by the source Observable, returning true if they pass the filter
returns
an Observable that emits only those items in the original Observable for which the filter evaluates as true
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
def find(p: (T) ⇒ Boolean): Observable[T]

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.
p
a function that evaluates the items emitted by the source Observable, returning true if they pass the filter
returns
an Observable that emits only the first item in the original Observable for which the filter evaluates as true
def firstOrElse[U >: T](default: ⇒ U): Observable[U]

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.
def flatMap[U](f: (T) ⇒ Observable[U]): Observable[U]

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 concatenating those resulting Observables and emitting the results of this concatenation.
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 concatenating those resulting Observables and emitting the results of this concatenation.
f
a function that, when applied to an item emitted by the source Observable, returns an Observable
returns
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.
def flatMapDelayError[U](f: (T) ⇒ Observable[U]): Observable[U]

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 concatenating those resulting Observables and emitting the results of this concatenation.
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 concatenating those resulting Observables and emitting the results of this concatenation.
It's an alias for Observable!.concatMapDelayError.
f
a function that, when applied to an item emitted by the source Observable, returns an Observable
returns
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.
def flatMapLatest[U](f: (T) ⇒ Observable[U]): Observable[U]

An alias of Observable!.switchMap.
An alias of Observable!.switchMap.
Returns a new Observable that emits the items emitted by the Observable most recently generated by the mapping function.
def flatScan[R](initial: R)(op: (R, T) ⇒ Observable[R]): Observable[R]

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.
It's the combination between scan and monifu.reactive.Observable.flatten.
def flatScanDelayError[R](initial: R)(op: (R, T) ⇒ Observable[R]): Observable[R]

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.
It's the combination between scan and monifu.reactive.Observable.flattenDelayError.
def flatten[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

Alias for Observable!.concat.
Alias for Observable!.concat.
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 Observable by using this method.
The difference between the concat operation and merge is that concat 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, Observable!.concat is safe to use in all contexts, whereas merge requires buffering.
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def flattenDelayError[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

Alias for Observable!.concatDelayError.
Alias for Observable!.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 Observable by using this method.
The difference between the concat operation and merge is that concat 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, Observable!.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) along to the observers. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def flattenLatest[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

Alias for Observable!.switch
Alias for Observable!.switch
Convert an Observable that emits Observables into a single Observable that emits the items emitted by the most-recently-emitted of those Observables.
def foldLeft[R](initial: R)(op: (R, T) ⇒ R): Observable[R]

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.
def forAll(p: (T) ⇒ Boolean): Observable[Boolean]

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.
p
a function that evaluates the items emitted by the source Observable, returning true if they pass the filter
returns
an Observable that emits only true or false in case the given predicate holds or not for all the items
def foreach(cb: (T) ⇒ Unit)(implicit s: Scheduler): Unit

Subscribes to the source Observable and foreach element emitted by the source it executes the given callback.
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def groupBy[K](keyBufferSize: Int, keySelector: (T) ⇒ K): Observable[GroupedObservable[K, T]]

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.
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).
This variant of groupBy specifies a keyBufferSize representing the size of the buffer that holds our keys. We cannot block when emitting new GroupedObservable. So by specifying a buffer size, on overflow the resulting observable will terminate with an onError.
keyBufferSize
- the buffer size used for buffering keys
keySelector
- a function that extracts the key for each item
def groupBy[K](keySelector: (T) ⇒ K): Observable[GroupedObservable[K, T]]

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).
keySelector
- a function that extracts the key for each item
def hashCode(): Int

Definition Classes
AnyRef → Any
def head: Observable[T]

Only emits the first element emitted by the source observable, after which it's completed immediately.
def headOrElse[B >: T](default: ⇒ B): Observable[B]

Emits the first element emitted by the source, or otherwise if the source is completed without emitting anything, then the default is emitted.
def ignoreElements: Observable[Nothing]

Alias for Observable!.complete.
Alias for Observable!.complete.
Ignores all items emitted by the source Observable and only calls onCompleted or onError.
returns
an empty Observable that only calls onCompleted or onError, based on which one is called by the source Observable
def isEmpty: Observable[Boolean]

Returns an Observable that emits true if the source Observable is empty, otherwise false.
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
def last: Observable[T]

Only emits the last element emitted by the source observable, after which it's completed immediately.
def lift[U](f: (Observable[T]) ⇒ Observable[U]): Observable[U]

Given a function that transforms an Observable[T] into an Observable[U], it transforms the source observable into an Observable[U].
def map[U](f: (T) ⇒ U): Observable[U]

Returns an Observable that applies the given function to each item emitted by an Observable and emits the result.
Returns an Observable that applies the given function to each item emitted by an Observable and emits the result.
f
a function to apply to each item emitted by the Observable
returns
an Observable that emits the items from the source Observable, transformed by the given function
def materialize: Observable[Notification[T]]

Converts the source Observable that emits T into an Observable that emits Notification[T].
Converts the source Observable that emits T into an Observable that emits Notification[T].
NOTE: onComplete is still emitted after an onNext(OnComplete) notification however an onError(ex) notification is emitted as an onNext(OnError(ex)) followed by an onComplete.
def max[U >: T](implicit ev: Ordering[U]): Observable[U]

Takes the elements of the source Observable and emits the maximum value, after the source has completed.
def maxBy[U](f: (T) ⇒ U)(implicit ev: Ordering[U]): Observable[T]

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.
def merge[U](overflowStrategy: Evicted, onOverflow: (Long) ⇒ U)(implicit ev: <:<[T, Observable[U]]): Observable[U]

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 method.
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
onOverflow
- 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)
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def merge[U](overflowStrategy: OverflowStrategy)(implicit ev: <:<[T, Observable[U]]): Observable[U]

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 method.
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
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def merge[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

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 method.
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this

Note
this operation needs to do buffering and by not specifying an OverflowStrategy, the default strategy is being used.
def mergeDelayErrors[U](overflowStrategy: Evicted, onOverflow: (Long) ⇒ U)(implicit ev: <:<[T, Observable[U]]): Observable[U]

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 method.
This version is reserving onError notifications until all of the Observables complete and only then passing the issued errors(s) along to the observers. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
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
onOverflow
- 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)
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def mergeDelayErrors[U](overflowStrategy: OverflowStrategy)(implicit ev: <:<[T, Observable[U]]): Observable[U]

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 method.
This version is reserving onError notifications until all of the Observables complete and only then passing the issued errors(s) along to the observers. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
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
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this
def mergeDelayErrors[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

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 method.
This version is reserving onError notifications until all of the Observables complete and only then passing the issued errors(s) along to the observers. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
returns
an Observable that emits items that are the result of flattening the items emitted by the Observables emitted by this

Note
this operation needs to do buffering and by not specifying an OverflowStrategy, the default strategy is being used.
def mergeMap[U](f: (T) ⇒ Observable[U]): Observable[U]

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 Observables 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 Observables and emitting the results of this merger.
This function is the equivalent of observable.map(f).merge.
The difference between concat and merge is that concat 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, concat is safe to use in all contexts, whereas merge requires buffering.
f
- the transformation function
returns
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.
def mergeMapDelayErrors[U](f: (T) ⇒ Observable[U]): Observable[U]

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 Observables 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 Observables and emitting the results of this merger.
This function is the equivalent of observable.map(f).merge.
The difference between concat and merge is that concat 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, 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) along to the observers. Note that the streamed error is a CompositeException, since multiple errors from multiple streams can happen.
f
- the transformation function
returns
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.
def min[U >: T](implicit ev: Ordering[U]): Observable[U]

Takes the elements of the source Observable and emits the minimum value, after the source has completed.
def minBy[U](f: (T) ⇒ U)(implicit ev: Ordering[U]): Observable[T]

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.
def multicast[U >: T, R](subject: Subject[U, R])(implicit s: Scheduler): ConnectableObservable[R]

Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e.
Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e. whose source is shared by all observers).
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def nonEmpty: Observable[Boolean]

Returns an Observable that emits false if the source Observable is empty, otherwise true.
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def onErrorFallbackTo[U >: T](that: ⇒ Observable[U]): Observable[U]

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.
that
- a backup sequence that's being subscribed in case the source terminates with an error.
def onErrorRecoverWith[U >: T](pf: PartialFunction[Throwable, Observable[U]]): Observable[U]

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 partial 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 partial 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.
NOTE that compared with onErrorResumeNext from Rx.NET, the streaming is not resumed in case the source is terminated normally with an onComplete.
pf
- a partial function that matches errors with a backup throwable that is subscribed when the source throws an error.
def onErrorRetry(maxRetries: Long): Observable[T]

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.
def onErrorRetryIf(p: (Throwable) ⇒ Boolean): Observable[T]

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.
def onErrorRetryUnlimited: Observable[T]

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).onErrorRetryUnlimited will loop forever.
def onSubscribe(observer: Observer[T])(implicit s: Scheduler): Unit

Subscribes to the stream.
Subscribes to the stream.
This function is "unsafe" to call because it does not protect the calls to the given Observer implementation in regards to unexpected exceptions that violate the contract, therefore the given instance must respect its contract and not throw any exceptions when the observable calls onNext, onComplete and onError. If it does, then the behavior is undefined.
observer
is an Observer that respects the Monifu Rx contract
s
is the Scheduler used for creating the subscription
def publish(implicit s: Scheduler): ConnectableObservable[T]

Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e.
Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e. whose source is shared by all observers). The underlying subject used is a PublishSubject.
def publishLast(implicit s: Scheduler): ConnectableObservable[T]

Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e.
Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e. whose source is shared by all observers). The underlying subject used is a AsyncSubject.
def reduce[U >: T](op: (U, U) ⇒ U): Observable[U]

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.
def repeat: Observable[T]

Repeats the items emitted by this Observable continuously.
Repeats the items emitted by this Observable continuously. It caches the generated items until onComplete and repeats them ad infinitum. On error it terminates.
def replay(bufferSize: Int)(implicit s: Scheduler): ConnectableObservable[T]

Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e.
Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e. whose source is shared by all observers). The underlying subject used is a ReplaySubject.
bufferSize
is the size of the buffer limiting the number of items that can be replayed (on overflow the head starts being dropped)
def replay(implicit s: Scheduler): ConnectableObservable[T]

Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e.
Converts this observable into a multicast observable, useful for turning a cold observable into a hot one (i.e. whose source is shared by all observers). The underlying subject used is a ReplaySubject.
def sample[U](sampler: Observable[U]): Observable[T]

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.
Use the sample() method 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.
sampler
- the Observable to use for sampling the source Observable
def sample(initialDelay: FiniteDuration, delay: FiniteDuration): Observable[T]

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.
Use the sample() method 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.
initialDelay
the initial delay after which sampling can happen
delay
the timespan at which sampling occurs and note that this is not accurate as it is subject to back-pressure concerns - as in if the delay is 1 second and the processing of an event on onNext in the observer takes one second, then the actual sampling delay will be 2 seconds.
def sample(delay: FiniteDuration): Observable[T]

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.
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.
delay
the timespan at which sampling occurs and note that this is not accurate as it is subject to back-pressure concerns - as in if the delay is 1 second and the processing of an event on onNext in the observer takes one second, then the actual sampling delay will be 2 seconds.
def sampleRepeated[U](sampler: Observable[U]): Observable[T]

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, the emit the last emitted value anyway.
sampler
- the Observable to use for sampling the source Observable

See also
Observable.sample
def sampleRepeated(initialDelay: FiniteDuration, delay: FiniteDuration): Observable[T]

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, the emit the last emitted value anyway.
Also see sample.
initialDelay
the initial delay after which sampling can happen
delay
the timespan at which sampling occurs and note that this is not accurate as it is subject to back-pressure concerns - as in if the delay is 1 second and the processing of an event on onNext in the observer takes one second, then the actual sampling delay will be 2 seconds.
def sampleRepeated(delay: FiniteDuration): Observable[T]

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, the emit the last emitted value anyway.
Also see Observable.sample.
delay
the timespan at which sampling occurs and note that this is not accurate as it is subject to back-pressure concerns - as in if the delay is 1 second and the processing of an event on onNext in the observer takes one second, then the actual sampling delay will be 2 seconds.
def scan[R](initial: R)(op: (R, T) ⇒ R): Observable[R]

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 foldLeft, but emits the state on each step. Useful for modeling finite state machines.
def share(implicit s: Scheduler): Observable[T]

Returns a new Observable that multi-casts (shares) the original Observable.
def startWith[U >: T](elems: U*): Observable[U]

Creates a new Observable that emits the given elements and then it also emits the events of the source (prepend operation).
def subscribe(nextFn: (T) ⇒ Future[Ack])(implicit s: Scheduler): BooleanCancelable

Subscribes to the stream.
Subscribes to the stream.
returns
a subscription that can be used to cancel the streaming.
def subscribe()(implicit s: Scheduler): Cancelable

Subscribes to the stream.
Subscribes to the stream.
returns
a subscription that can be used to cancel the streaming.
def subscribe(nextFn: (T) ⇒ Future[Ack], errorFn: (Throwable) ⇒ Unit)(implicit s: Scheduler): BooleanCancelable

Subscribes to the stream.
Subscribes to the stream.
returns
a subscription that can be used to cancel the streaming.
def subscribe(nextFn: (T) ⇒ Future[Ack], errorFn: (Throwable) ⇒ Unit, completedFn: () ⇒ Unit)(implicit s: Scheduler): BooleanCancelable

Subscribes to the stream.
Subscribes to the stream.
returns
a subscription that can be used to cancel the streaming.
def subscribe(observer: Observer[T])(implicit s: Scheduler): BooleanCancelable

Subscribes to the stream.
Subscribes to the stream.
returns
a subscription that can be used to cancel the streaming.
def subscribe(subscriber: Subscriber[T]): BooleanCancelable

Subscribes to the stream.
Subscribes to the stream.
returns
a subscription that can be used to cancel the streaming.
def subscribeOn(s: Scheduler): Observable[T]

Returns a new Observable that uses the specified Scheduler for initiating the subscription.
def sum[U >: T](implicit ev: Numeric[U]): Observable[U]

Given a source that emits numeric values, the sum operator sums up all values and at onComplete it emits the total.
def switch[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

Convert an Observable that emits Observables into a single Observable that emits the items emitted by the most-recently-emitted of those Observables.
def switchMap[U](f: (T) ⇒ Observable[U]): Observable[U]

Returns a new Observable that emits the items emitted by the Observable most recently generated by the mapping function.
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def tail: Observable[T]

Drops the first element of the source observable, emitting the rest.
def take(timespan: FiniteDuration): Observable[T]

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.
timespan
the window of time during which the new Observable is allowed to emit the events of the source
def take(n: Long): Observable[T]

Selects the first n elements (from the start).
Selects the first n elements (from the start).
n
the number of elements to take
returns
a new Observable that emits only the first n elements from the source
def takeRight(n: Int): Observable[T]

Creates a new Observable that only emits the last n elements emitted by the source.
def takeWhile(p: (T) ⇒ Boolean): Observable[T]

Takes longest prefix of elements that satisfy the given predicate and returns a new Observable that emits those elements.
def takeWhileNotCanceled(c: BooleanCancelable): Observable[T]

Takes longest prefix of elements that satisfy the given predicate and returns a new Observable that emits those elements.
def throttleFirst(interval: FiniteDuration): Observable[T]

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.
interval
time to wait before emitting another item after emitting the last item
def throttleLast(period: FiniteDuration): Observable[T]

Returns an Observable that emits only the last item emitted by the source Observable during sequential time windows of a specified duration.
Returns an Observable that emits only the last item emitted by the source Observable during sequential time windows of a specified duration.
This differs from Observable!.throttleFirst in that this ticks along at a scheduled interval whereas throttleFirst does not tick, it just tracks passage of time.
period
- duration of windows within which the last item emitted by the source Observable will be emitted
def throttleWithTimeout(timeout: FiniteDuration): Observable[T]

Alias for debounce.
Alias for debounce.
Returns an Observable that only emits those items emitted by the source Observable that are not followed by another emitted item within a specified time window.
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.
timeout
- 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
def timeout[U >: T](timeout: FiniteDuration, backup: Observable[U]): Observable[U]

Returns an Observable that mirrors the source Observable but applies a timeout overflowStrategy for each emitted item.
Returns an Observable that mirrors the source Observable but applies a timeout overflowStrategy for each emitted item. If the next item isn't emitted within the specified timeout duration starting from its predecessor, the resulting Observable begins instead to mirror a backup Observable.
timeout
maximum duration between emitted items before a timeout occurs
backup
is the backup observable to subscribe to in case of a timeout
def timeout(timeout: FiniteDuration): Observable[T]

Returns an Observable that mirrors the source Observable but applies a timeout overflowStrategy for each emitted item.
Returns an Observable that mirrors the source Observable but applies a timeout overflowStrategy for each emitted item. 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.
timeout
maximum duration between emitted items before a timeout occurs
def toReactive[U >: T](implicit s: Scheduler): Publisher[U]

Wraps this Observable into a org.reactivestreams.Publisher.
Wraps this Observable into a org.reactivestreams.Publisher. See the Reactive Streams protocol that Monifu implements.
def toString(): String

Definition Classes
AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
def whileBusyBuffer[U >: T](overflowStrategy: Evicted, onOverflow: (Long) ⇒ U): Observable[U]

While the destination observer is busy, buffers events, applying the given overflowStrategy.
While the destination observer is busy, buffers events, applying the given overflowStrategy.
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
onOverflow
- 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)
def whileBusyBuffer[U >: T](overflowStrategy: Synchronous): Observable[U]

While the destination observer is busy, buffers events, applying the given overflowStrategy.
While the destination observer is busy, buffers events, applying the given overflowStrategy.
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
def whileBusyDropEvents[U >: T](onOverflow: (Long) ⇒ U): Observable[U]

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.
onOverflow
- 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)
def whileBusyDropEvents: Observable[T]

While the destination observer is busy, drop the incoming events.
def window(timespan: FiniteDuration, maxCount: Int): Observable[Observable[T]]

Periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time.
Periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time.
The resulting Observable emits connected, non-overlapping windows, each of a fixed duration specified by the timespan argument. When the source Observable completes or encounters an error, the resulting Observable emits the current window and propagates the notification from the source Observable.
timespan
the interval of time at which it should complete the current window and emit a new one
maxCount
the maximum size of each window
def window(timespan: FiniteDuration): Observable[Observable[T]]

Periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time.
Periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time.
The resulting Observable emits connected, non-overlapping windows, each of a fixed duration specified by the timespan argument. When the source Observable completes or encounters an error, the resulting Observable emits the current window and propagates the notification from the source Observable.
timespan
the interval of time at which it should complete the current window and emit a new one
def window(count: Int, skip: Int): Observable[Observable[T]]

Returns an Observable that emits windows of items it collects from the source Observable.
Returns an Observable that emits windows of items it collects from the source Observable. The resulting Observable emits windows every skip items, each containing no more than count items. When the source Observable completes or encounters an error, the resulting Observable emits the current window and propagates the notification from the source Observable.
There are 3 possibilities:
1. in case skip == count, then there are no items dropped and no overlap, the call being equivalent to window(count) 2. in case skip < count, then overlap between windows happens, with the number of elements being repeated being count - skip 3. in case skip > count, then skip - count elements start getting dropped between windows
count
- the maximum size of each window before it should be emitted
skip
- how many items need to be skipped before starting a new window
def window(count: Int): Observable[Observable[T]]

Periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time.
Periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time.
This variant of window opens its first window immediately. It closes the currently open window and immediately opens a new one whenever the current window has emitted count items. It will also close the currently open window if it receives an onCompleted or onError notification from the source Observable. This variant of window emits a series of non-overlapping windows whose collective emissions correspond one-to-one with those of the source Observable.
count
the bundle size
def zip[U](other: Observable[U]): Observable[(T, U)]

Creates a new Observable from this Observable and another given Observable, by emitting elements combined in pairs.
Creates a new Observable from this Observable and another given Observable, by emitting elements combined in pairs. If one of the Observable emits fewer events than the other, then the rest of the unpaired events are ignored.
def zipWithIndex: Observable[(T, Long)]

Zips the emitted elements of the source with their indices.

Related Docs: object Observable | package reactive

trait Observable[+T] extends AnyRef

Interface

Contract

On Dealing with the contract

Abstract Value Members

abstract def onSubscribe(subscriber: Subscriber[T]): Unit

Concrete Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

def ++[U >: T](other: ⇒ Observable[U]): Observable[U]

def +:[U >: T](elem: U): Observable[U]

def :+[U >: T](elem: U): Observable[U]

final def ==(arg0: Any): Boolean

def ambWith[U >: T](other: Observable[U]): Observable[U]

def asFuture(implicit s: Scheduler): Future[Option[T]]

final def asInstanceOf[T0]: T0

def asyncBoundary[U >: T](overflowStrategy: Evicted, onOverflow: (Long) ⇒ U): Observable[U]

def asyncBoundary(overflowStrategy: OverflowStrategy): Observable[T]

def behavior[U >: T](initialValue: U)(implicit s: Scheduler): ConnectableObservable[U]

def buffer(timespan: FiniteDuration, maxSize: Int): Observable[Seq[T]]

def buffer(timespan: FiniteDuration): Observable[Seq[T]]

def buffer(count: Int, skip: Int): Observable[Seq[T]]

def buffer(count: Int): Observable[Seq[T]]

def bufferIntrospective(maxSize: Int): Observable[List[T]]

def cache(maxCapacity: Int): Observable[T]

def cache: Observable[T]

def clone(): AnyRef

def collect[U](pf: PartialFunction[T, U]): Observable[U]

def combineLatest[U](other: Observable[U]): Observable[(T, U)]

def combineLatestDelayError[U](other: Observable[U]): Observable[(T, U)]

def complete: Observable[Nothing]

def concat[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

def concatDelayError[U](implicit ev: <:<[T, Observable[U]]): Observable[U]

def concatMap[U](f: (T) ⇒ Observable[U]): Observable[U]

def concatMapDelayError[U](f: (T) ⇒ Observable[U]): Observable[U]

def count: Observable[Long]

def debounce[U](selector: (T) ⇒ Observable[Any], f: (T) ⇒ Observable[U]): Observable[U]

def debounce(selector: (T) ⇒ Observable[Any]): Observable[T]

def debounce[U](timeout: FiniteDuration, f: (T) ⇒ Observable[U]): Observable[U]

def debounce(timeout: FiniteDuration): Observable[T]

def debounceRepeated(period: FiniteDuration): Observable[T]

def defaultIfEmpty[U >: T](default: U): Observable[U]

def delay[U](selector: (T) ⇒ Observable[U]): Observable[T]

def delay(duration: FiniteDuration): Observable[T]

def delaySubscription(timespan: FiniteDuration): Observable[T]

def delaySubscription[U](trigger: Observable[U]): Observable[T]

def distinct[U](fn: (T) ⇒ U): Observable[T]

def distinct: Observable[T]

def distinctUntilChanged[U](fn: (T) ⇒ U): Observable[T]

def distinctUntilChanged: Observable[T]

def doOnCanceled(cb: ⇒ Unit): Observable[T]

def doOnComplete(cb: ⇒ Unit): Observable[T]

def doOnError(cb: (Throwable) ⇒ Unit): Observable[T]

def doOnStart(cb: (T) ⇒ Unit): Observable[T]

def doWork(cb: (T) ⇒ Unit): Observable[T]

def drop(n: Int): Observable[T]

def dropByTimespan(timespan: FiniteDuration): Observable[T]

def dropWhile(p: (T) ⇒ Boolean): Observable[T]

def dropWhileWithIndex(p: (T, Int) ⇒ Boolean): Observable[T]

def dump(prefix: String, out: PrintStream = System.out): Observable[T]

def echoOnce(timeout: FiniteDuration): Observable[T]

def echoRepeated(timeout: FiniteDuration): Observable[T]

def endWith[U >: T](elems: U*): Observable[U]

def endWithError(error: Throwable): Observable[T]

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def error: Observable[Throwable]

def exists(p: (T) ⇒ Boolean): Observable[Boolean]

def filter(p: (T) ⇒ Boolean): Observable[T]

def finalize(): Unit

def find(p: (T) ⇒ Boolean): Observable[T]

def firstOrElse[U >: T](default: ⇒ U): Observable[U]

def flatMap[U](f: (T) ⇒ Observable[U]): Observable[U]

def flatMapDelayError[U](f: (T) ⇒ Observable[U]): Observable[U]

def flatMapLatest[U](f: (T) ⇒ Observable[U]): Observable[U]

def flatScan[R](initial: R)(op: (R, T) ⇒ Observable[R]): Observable[R]

def flatScanDelayError[R](initial: R)(op: (R, T) ⇒ Observable[R]): Observable[R]

def flatten[U](implicit ev: <:<[T, Observable[U]]): Observable[U]