/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License is
* distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
* the License for the specific language governing permissions and limitations under the License.
*/
package io.reactivex.internal.operators.observable;
import java.util.concurrent.
TimeUnit;
import java.util.concurrent.atomic.*;
import io.reactivex.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.internal.disposables.
DisposableHelper;
/**
* Emits the next or latest item when the given time elapses.
* <p>
* The operator emits the next item, then starts a timer. When the timer fires,
* it tries to emit the latest item from upstream. If there was no upstream item,
* in the meantime, the next upstream item is emitted immediately and the
* timed process repeats.
* <p>History: 2.1.14 - experimental
* @param <T> the upstream and downstream value type
* @since 2.2
*/
public final class
ObservableThrottleLatest<T> extends
AbstractObservableWithUpstream<T, T> {
final long
timeout;
final
TimeUnit unit;
final
Scheduler scheduler;
final boolean
emitLast;
public
ObservableThrottleLatest(
Observable<T>
source,
long
timeout,
TimeUnit unit,
Scheduler scheduler,
boolean
emitLast) {
super(
source);
this.
timeout =
timeout;
this.
unit =
unit;
this.
scheduler =
scheduler;
this.
emitLast =
emitLast;
}
@
Override
protected void
subscribeActual(
Observer<? super T>
observer) {
source.
subscribe(new
ThrottleLatestObserver<T>(
observer,
timeout,
unit,
scheduler.
createWorker(),
emitLast));
}
static final class
ThrottleLatestObserver<T>
extends
AtomicInteger
implements
Observer<T>,
Disposable,
Runnable {
private static final long
serialVersionUID = -8296689127439125014L;
final
Observer<? super T>
downstream;
final long
timeout;
final
TimeUnit unit;
final
Scheduler.
Worker worker;
final boolean
emitLast;
final
AtomicReference<T>
latest;
Disposable upstream;
volatile boolean
done;
Throwable error;
volatile boolean
cancelled;
volatile boolean
timerFired;
boolean
timerRunning;
ThrottleLatestObserver(
Observer<? super T>
downstream,
long
timeout,
TimeUnit unit,
Scheduler.
Worker worker,
boolean
emitLast) {
this.
downstream =
downstream;
this.
timeout =
timeout;
this.
unit =
unit;
this.
worker =
worker;
this.
emitLast =
emitLast;
this.
latest = new
AtomicReference<T>();
}
@
Override
public void
onSubscribe(
Disposable d) {
if (
DisposableHelper.
validate(
upstream,
d)) {
upstream =
d;
downstream.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
latest.
set(
t);
drain();
}
@
Override
public void
onError(
Throwable t) {
error =
t;
done = true;
drain();
}
@
Override
public void
onComplete() {
done = true;
drain();
}
@
Override
public void
dispose() {
cancelled = true;
upstream.
dispose();
worker.
dispose();
if (
getAndIncrement() == 0) {
latest.
lazySet(null);
}
}
@
Override
public boolean
isDisposed() {
return
cancelled;
}
@
Override
public void
run() {
timerFired = true;
drain();
}
void
drain() {
if (
getAndIncrement() != 0) {
return;
}
int
missed = 1;
AtomicReference<T>
latest = this.
latest;
Observer<? super T>
downstream = this.
downstream;
for (;;) {
for (;;) {
if (
cancelled) {
latest.
lazySet(null);
return;
}
boolean
d =
done;
if (
d &&
error != null) {
latest.
lazySet(null);
downstream.
onError(
error);
worker.
dispose();
return;
}
T
v =
latest.
get();
boolean
empty =
v == null;
if (
d) {
v =
latest.
getAndSet(null);
if (!
empty &&
emitLast) {
downstream.
onNext(
v);
}
downstream.
onComplete();
worker.
dispose();
return;
}
if (
empty) {
if (
timerFired) {
timerRunning = false;
timerFired = false;
}
break;
}
if (!
timerRunning ||
timerFired) {
v =
latest.
getAndSet(null);
downstream.
onNext(
v);
timerFired = false;
timerRunning = true;
worker.
schedule(this,
timeout,
unit);
} else {
break;
}
}
missed =
addAndGet(-
missed);
if (
missed == 0) {
break;
}
}
}
}
}