io.reactivex.rxjava3.internal.operators.flowable.FlowableFlattenIterable Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of rxjava Show documentation
Show all versions of rxjava Show documentation
Reactive Extensions for Java
/*
* 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.rxjava3.internal.operators.flowable;
import java.util.*;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import io.reactivex.rxjava3.annotations.Nullable;
import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.exceptions.*;
import io.reactivex.rxjava3.functions.*;
import io.reactivex.rxjava3.internal.subscriptions.*;
import io.reactivex.rxjava3.internal.util.*;
import io.reactivex.rxjava3.operators.QueueSubscription;
import io.reactivex.rxjava3.operators.SimpleQueue;
import io.reactivex.rxjava3.operators.SpscArrayQueue;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;
public final class FlowableFlattenIterable extends AbstractFlowableWithUpstream {
final Function> mapper;
final int prefetch;
public FlowableFlattenIterable(Flowable source,
Function> mapper, int prefetch) {
super(source);
this.mapper = mapper;
this.prefetch = prefetch;
}
@SuppressWarnings("unchecked")
@Override
public void subscribeActual(Subscriber s) {
if (source instanceof Supplier) {
T v;
try {
v = ((Supplier)source).get();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
EmptySubscription.error(ex, s);
return;
}
if (v == null) {
EmptySubscription.complete(s);
return;
}
Iterator it;
try {
Iterable iterable = mapper.apply(v);
it = iterable.iterator();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
EmptySubscription.error(ex, s);
return;
}
FlowableFromIterable.subscribe(s, it);
return;
}
source.subscribe(new FlattenIterableSubscriber<>(s, mapper, prefetch));
}
/**
* Create a {@link Subscriber} with the given parameters.
* @param the upstream value type
* @param the {@link Iterable} and output value type
* @param downstream the downstream {@code Subscriber} to wrap
* @param mapper the mapper function
* @param prefetch the number of items to prefetch
* @return the new {@code Subscriber}
*/
public static Subscriber subscribe(Subscriber downstream, Function> mapper, int prefetch) {
return new FlattenIterableSubscriber<>(downstream, mapper, prefetch);
}
static final class FlattenIterableSubscriber
extends BasicIntQueueSubscription
implements FlowableSubscriber {
private static final long serialVersionUID = -3096000382929934955L;
final Subscriber downstream;
final Function> mapper;
final int prefetch;
final int limit;
final AtomicLong requested;
Subscription upstream;
SimpleQueue queue;
volatile boolean done;
volatile boolean cancelled;
final AtomicReference error;
Iterator current;
int consumed;
int fusionMode;
FlattenIterableSubscriber(Subscriber actual,
Function> mapper, int prefetch) {
this.downstream = actual;
this.mapper = mapper;
this.prefetch = prefetch;
this.limit = prefetch - (prefetch >> 2);
this.error = new AtomicReference<>();
this.requested = new AtomicLong();
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.upstream, s)) {
this.upstream = s;
if (s instanceof QueueSubscription) {
@SuppressWarnings("unchecked")
QueueSubscription qs = (QueueSubscription) s;
int m = qs.requestFusion(ANY);
if (m == SYNC) {
fusionMode = m;
this.queue = qs;
done = true;
downstream.onSubscribe(this);
return;
}
if (m == ASYNC) {
fusionMode = m;
this.queue = qs;
downstream.onSubscribe(this);
s.request(prefetch);
return;
}
}
queue = new SpscArrayQueue<>(prefetch);
downstream.onSubscribe(this);
s.request(prefetch);
}
}
@Override
public void onNext(T t) {
if (done) {
return;
}
if (fusionMode == NONE && !queue.offer(t)) {
onError(new MissingBackpressureException("Queue is full?!"));
return;
}
drain();
}
@Override
public void onError(Throwable t) {
if (!done && ExceptionHelper.addThrowable(error, t)) {
done = true;
drain();
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public void onComplete() {
if (done) {
return;
}
done = true;
drain();
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
BackpressureHelper.add(requested, n);
drain();
}
}
@Override
public void cancel() {
if (!cancelled) {
cancelled = true;
upstream.cancel();
if (getAndIncrement() == 0) {
queue.clear();
}
}
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
final Subscriber a = downstream;
final SimpleQueue q = queue;
final boolean replenish = fusionMode != SYNC;
int missed = 1;
Iterator it = current;
for (;;) {
if (it == null) {
boolean d = done;
T t;
try {
t = q.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
upstream.cancel();
ExceptionHelper.addThrowable(error, ex);
ex = ExceptionHelper.terminate(error);
current = null;
q.clear();
a.onError(ex);
return;
}
boolean empty = t == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
if (t != null) {
Iterable iterable;
boolean b;
try {
iterable = mapper.apply(t);
it = iterable.iterator();
b = it.hasNext();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
upstream.cancel();
ExceptionHelper.addThrowable(error, ex);
ex = ExceptionHelper.terminate(error);
a.onError(ex);
return;
}
if (!b) {
it = null;
consumedOne(replenish);
continue;
}
current = it;
}
}
if (it != null) {
long r = requested.get();
long e = 0L;
while (e != r) {
if (checkTerminated(done, false, a, q)) {
return;
}
R v;
try {
v = Objects.requireNonNull(it.next(), "The iterator returned a null value");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
current = null;
upstream.cancel();
ExceptionHelper.addThrowable(error, ex);
ex = ExceptionHelper.terminate(error);
a.onError(ex);
return;
}
a.onNext(v);
if (checkTerminated(done, false, a, q)) {
return;
}
e++;
boolean b;
try {
b = it.hasNext();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
current = null;
upstream.cancel();
ExceptionHelper.addThrowable(error, ex);
ex = ExceptionHelper.terminate(error);
a.onError(ex);
return;
}
if (!b) {
consumedOne(replenish);
it = null;
current = null;
break;
}
}
if (e == r) {
boolean d = done;
boolean empty = q.isEmpty() && it == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
}
if (e != 0L) {
if (r != Long.MAX_VALUE) {
requested.addAndGet(-e);
}
}
if (it == null) {
continue;
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
void consumedOne(boolean enabled) {
if (enabled) {
int c = consumed + 1;
if (c == limit) {
consumed = 0;
upstream.request(c);
} else {
consumed = c;
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber a, SimpleQueue q) {
if (cancelled) {
current = null;
q.clear();
return true;
}
if (d) {
Throwable ex = error.get();
if (ex != null) {
ex = ExceptionHelper.terminate(error);
current = null;
q.clear();
a.onError(ex);
return true;
} else if (empty) {
a.onComplete();
return true;
}
}
return false;
}
@Override
public void clear() {
current = null;
queue.clear();
}
@Override
public boolean isEmpty() {
return current == null && queue.isEmpty();
}
@Nullable
@Override
public R poll() throws Throwable {
Iterator it = current;
for (;;) {
if (it == null) {
T v = queue.poll();
if (v == null) {
return null;
}
it = mapper.apply(v).iterator();
if (!it.hasNext()) {
it = null;
continue;
}
current = it;
}
R r = Objects.requireNonNull(it.next(), "The iterator returned a null value");
if (!it.hasNext()) {
current = null;
}
return r;
}
}
@Override
public int requestFusion(int requestedMode) {
if ((requestedMode & SYNC) != 0 && fusionMode == SYNC) {
return SYNC;
}
return NONE;
}
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy