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2.x: add sample() overload that can emit the very last buffered item (#…
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…4955)
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@akarnokd
akarnokd committed Jan 4, 2017
1 parent 479f89f commit 71330c0
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116 changes: 114 additions & 2 deletions src/main/java/io/reactivex/Flowable.java
View file
Expand Up @@ -11530,6 +11530,41 @@ public final Flowable<T> sample(long period, TimeUnit unit) {
return sample(period, unit, Schedulers.computation());
}

/**
* Returns a Flowable that emits the most recently emitted item (if any) emitted by the source Publisher
* within periodic time intervals and optionally emit the very last upstream item when the upstream completes.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.png" alt="">
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>This operator does not support backpressure as it uses time to control data flow.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code sample} operates by default on the {@code computation} {@link Scheduler}.</dd>
* </dl>
*
* @param period
* the sampling rate
* @param unit
* the {@link TimeUnit} in which {@code period} is defined
* @param emitLast
* if true and the upstream completes while there is still an unsampled item available,
* that item is emitted to downstream before completion
* if false, an unsampled last item is ignored.
* @return a Flowable that emits the results of sampling the items emitted by the source Publisher at
* the specified time interval
* @see <a href="http://reactivex.io/documentation/operators/sample.html">ReactiveX operators documentation: Sample</a>
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Backpressure">RxJava wiki: Backpressure</a>
* @see #throttleLast(long, TimeUnit)
* @since 2.0.5 - experimental
*/
@CheckReturnValue
@BackpressureSupport(BackpressureKind.ERROR)
@SchedulerSupport(SchedulerSupport.COMPUTATION)
@Experimental
public final Flowable<T> sample(long period, TimeUnit unit, boolean emitLast) {
return sample(period, unit, Schedulers.computation(), emitLast);
}

/**
* Returns a Flowable that emits the most recently emitted item (if any) emitted by the source Publisher
* within periodic time intervals, where the intervals are defined on a particular Scheduler.
Expand Down Expand Up @@ -11560,7 +11595,47 @@ public final Flowable<T> sample(long period, TimeUnit unit) {
public final Flowable<T> sample(long period, TimeUnit unit, Scheduler scheduler) {
ObjectHelper.requireNonNull(unit, "unit is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new FlowableSampleTimed<T>(this, period, unit, scheduler));
return RxJavaPlugins.onAssembly(new FlowableSampleTimed<T>(this, period, unit, scheduler, false));
}

/**
* Returns a Flowable that emits the most recently emitted item (if any) emitted by the source Publisher
* within periodic time intervals, where the intervals are defined on a particular Scheduler
* and optionally emit the very last upstream item when the upstream completes.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.s.png" alt="">
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>This operator does not support backpressure as it uses time to control data flow.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>You specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param period
* the sampling rate
* @param unit
* the {@link TimeUnit} in which {@code period} is defined
* @param scheduler
* the {@link Scheduler} to use when sampling
* @param emitLast
* if true and the upstream completes while there is still an unsampled item available,
* that item is emitted to downstream before completion
* if false, an unsampled last item is ignored.
* @return a Flowable that emits the results of sampling the items emitted by the source Publisher at
* the specified time interval
* @see <a href="http://reactivex.io/documentation/operators/sample.html">ReactiveX operators documentation: Sample</a>
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Backpressure">RxJava wiki: Backpressure</a>
* @see #throttleLast(long, TimeUnit, Scheduler)
* @since 2.0.5 - experimental
*/
@CheckReturnValue
@BackpressureSupport(BackpressureKind.ERROR)
@SchedulerSupport(SchedulerSupport.CUSTOM)
@Experimental
public final Flowable<T> sample(long period, TimeUnit unit, Scheduler scheduler, boolean emitLast) {
ObjectHelper.requireNonNull(unit, "unit is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new FlowableSampleTimed<T>(this, period, unit, scheduler, emitLast));
}

/**
Expand Down Expand Up @@ -11590,7 +11665,44 @@ public final Flowable<T> sample(long period, TimeUnit unit, Scheduler scheduler)
@SchedulerSupport(SchedulerSupport.NONE)
public final <U> Flowable<T> sample(Publisher<U> sampler) {
ObjectHelper.requireNonNull(sampler, "sampler is null");
return RxJavaPlugins.onAssembly(new FlowableSamplePublisher<T>(this, sampler));
return RxJavaPlugins.onAssembly(new FlowableSamplePublisher<T>(this, sampler, false));
}

/**
* Returns a Flowable that, when the specified {@code sampler} Publisher emits an item or completes,
* emits the most recently emitted item (if any) emitted by the source Publisher since the previous
* emission from the {@code sampler} Publisher
* and optionally emit the very last upstream item when the upstream or other Publisher complete.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.png" alt="">
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>This operator does not support backpressure as it uses the emissions of the {@code sampler}
* Publisher to control data flow.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>This version of {@code sample} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <U> the element type of the sampler Publisher
* @param sampler
* the Publisher to use for sampling the source Publisher
* @param emitLast
* if true and the upstream completes while there is still an unsampled item available,
* that item is emitted to downstream before completion
* if false, an unsampled last item is ignored.
* @return a Flowable that emits the results of sampling the items emitted by this Publisher whenever
* the {@code sampler} Publisher emits an item or completes
* @see <a href="http://reactivex.io/documentation/operators/sample.html">ReactiveX operators documentation: Sample</a>
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Backpressure">RxJava wiki: Backpressure</a>
* @since 2.0.5 - experimental
*/
@CheckReturnValue
@BackpressureSupport(BackpressureKind.ERROR)
@SchedulerSupport(SchedulerSupport.NONE)
@Experimental
public final <U> Flowable<T> sample(Publisher<U> sampler, boolean emitLast) {
ObjectHelper.requireNonNull(sampler, "sampler is null");
return RxJavaPlugins.onAssembly(new FlowableSamplePublisher<T>(this, sampler, emitLast));
}

/**
Expand Down
104 changes: 102 additions & 2 deletions src/main/java/io/reactivex/Observable.java
View file
Expand Up @@ -9610,6 +9610,37 @@ public final Observable<T> sample(long period, TimeUnit unit) {
return sample(period, unit, Schedulers.computation());
}

/**
* Returns an Observable that emits the most recently emitted item (if any) emitted by the source ObservableSource
* within periodic time intervals and optionally emit the very last upstream item when the upstream completes.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code sample} operates by default on the {@code computation} {@link Scheduler}.</dd>
* </dl>
*
* @param period
* the sampling rate
* @param unit
* the {@link TimeUnit} in which {@code period} is defined
* @return an Observable that emits the results of sampling the items emitted by the source ObservableSource at
* the specified time interval
* @param emitLast
* if true and the upstream completes while there is still an unsampled item available,
* that item is emitted to downstream before completion
* if false, an unsampled last item is ignored.
* @see <a href="http://reactivex.io/documentation/operators/sample.html">ReactiveX operators documentation: Sample</a>
* @see #throttleLast(long, TimeUnit)
* @since 2.0.5 - experimental
*/
@CheckReturnValue
@SchedulerSupport(SchedulerSupport.COMPUTATION)
@Experimental
public final Observable<T> sample(long period, TimeUnit unit, boolean emitLast) {
return sample(period, unit, Schedulers.computation(), emitLast);
}

/**
* Returns an Observable that emits the most recently emitted item (if any) emitted by the source ObservableSource
* within periodic time intervals, where the intervals are defined on a particular Scheduler.
Expand All @@ -9636,7 +9667,43 @@ public final Observable<T> sample(long period, TimeUnit unit) {
public final Observable<T> sample(long period, TimeUnit unit, Scheduler scheduler) {
ObjectHelper.requireNonNull(unit, "unit is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new ObservableSampleTimed<T>(this, period, unit, scheduler));
return RxJavaPlugins.onAssembly(new ObservableSampleTimed<T>(this, period, unit, scheduler, false));
}

/**
* Returns an Observable that emits the most recently emitted item (if any) emitted by the source ObservableSource
* within periodic time intervals, where the intervals are defined on a particular Scheduler
* and optionally emit the very last upstream item when the upstream completes.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.s.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>You specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param period
* the sampling rate
* @param unit
* the {@link TimeUnit} in which {@code period} is defined
* @param scheduler
* the {@link Scheduler} to use when sampling
* @param emitLast
* if true and the upstream completes while there is still an unsampled item available,
* that item is emitted to downstream before completion
* if false, an unsampled last item is ignored.
* @return an Observable that emits the results of sampling the items emitted by the source ObservableSource at
* the specified time interval
* @see <a href="http://reactivex.io/documentation/operators/sample.html">ReactiveX operators documentation: Sample</a>
* @see #throttleLast(long, TimeUnit, Scheduler)
* @since 2.0.5 - experimental
*/
@CheckReturnValue
@SchedulerSupport(SchedulerSupport.CUSTOM)
@Experimental
public final Observable<T> sample(long period, TimeUnit unit, Scheduler scheduler, boolean emitLast) {
ObjectHelper.requireNonNull(unit, "unit is null");
ObjectHelper.requireNonNull(scheduler, "scheduler is null");
return RxJavaPlugins.onAssembly(new ObservableSampleTimed<T>(this, period, unit, scheduler, emitLast));
}

/**
Expand All @@ -9662,7 +9729,40 @@ public final Observable<T> sample(long period, TimeUnit unit, Scheduler schedule
@SchedulerSupport(SchedulerSupport.NONE)
public final <U> Observable<T> sample(ObservableSource<U> sampler) {
ObjectHelper.requireNonNull(sampler, "sampler is null");
return RxJavaPlugins.onAssembly(new ObservableSampleWithObservable<T>(this, sampler));
return RxJavaPlugins.onAssembly(new ObservableSampleWithObservable<T>(this, sampler, false));
}

/**
* Returns an Observable that, when the specified {@code sampler} ObservableSource emits an item or completes,
* emits the most recently emitted item (if any) emitted by the source ObservableSource since the previous
* emission from the {@code sampler} ObservableSource
* and optionally emit the very last upstream item when the upstream or other ObservableSource complete.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/sample.o.png" alt="">
* <dl>
* ObservableSource to control data flow.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>This version of {@code sample} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <U> the element type of the sampler ObservableSource
* @param sampler
* the ObservableSource to use for sampling the source ObservableSource
* @param emitLast
* if true and the upstream completes while there is still an unsampled item available,
* that item is emitted to downstream before completion
* if false, an unsampled last item is ignored.
* @return an Observable that emits the results of sampling the items emitted by this ObservableSource whenever
* the {@code sampler} ObservableSource emits an item or completes
* @see <a href="http://reactivex.io/documentation/operators/sample.html">ReactiveX operators documentation: Sample</a>
* @since 2.0.5 - experimental
*/
@CheckReturnValue
@SchedulerSupport(SchedulerSupport.NONE)
@Experimental
public final <U> Observable<T> sample(ObservableSource<U> sampler, boolean emitLast) {
ObjectHelper.requireNonNull(sampler, "sampler is null");
return RxJavaPlugins.onAssembly(new ObservableSampleWithObservable<T>(this, sampler, emitLast));
}

/**
Expand Down

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