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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.observable;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.*;
import io.reactivex.rxjava3.core.ObservableSource;
import io.reactivex.rxjava3.core.Observer;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.exceptions.Exceptions;
import io.reactivex.rxjava3.functions.Function;
import io.reactivex.rxjava3.internal.disposables.*;
import io.reactivex.rxjava3.observables.GroupedObservable;
import io.reactivex.rxjava3.operators.SpscLinkedArrayQueue;
public final class ObservableGroupBy extends AbstractObservableWithUpstream> {
final Function keySelector;
final Function valueSelector;
final int bufferSize;
final boolean delayError;
public ObservableGroupBy(ObservableSource source,
Function keySelector, Function valueSelector,
int bufferSize, boolean delayError) {
super(source);
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
}
@Override
public void subscribeActual(Observer> t) {
source.subscribe(new GroupByObserver<>(t, keySelector, valueSelector, bufferSize, delayError));
}
public static final class GroupByObserver extends AtomicInteger implements Observer, Disposable {
private static final long serialVersionUID = -3688291656102519502L;
final Observer> downstream;
final Function keySelector;
final Function valueSelector;
final int bufferSize;
final boolean delayError;
final Map> groups;
static final Object NULL_KEY = new Object();
Disposable upstream;
final AtomicBoolean cancelled = new AtomicBoolean();
public GroupByObserver(Observer> actual, Function keySelector, Function valueSelector, int bufferSize, boolean delayError) {
this.downstream = actual;
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
this.groups = new ConcurrentHashMap<>();
this.lazySet(1);
}
@Override
public void onSubscribe(Disposable d) {
if (DisposableHelper.validate(this.upstream, d)) {
this.upstream = d;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
K key;
try {
key = keySelector.apply(t);
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
upstream.dispose();
onError(e);
return;
}
Object mapKey = key != null ? key : NULL_KEY;
GroupedUnicast group = groups.get(mapKey);
boolean newGroup = false;
if (group == null) {
// if the main has been cancelled, stop creating groups
// and skip this value
if (cancelled.get()) {
return;
}
group = GroupedUnicast.createWith(key, bufferSize, this, delayError);
groups.put(mapKey, group);
getAndIncrement();
newGroup = true;
}
V v;
try {
v = Objects.requireNonNull(valueSelector.apply(t), "The value supplied is null");
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
upstream.dispose();
if (newGroup) {
downstream.onNext(group);
}
onError(e);
return;
}
group.onNext(v);
if (newGroup) {
downstream.onNext(group);
if (group.state.tryAbandon()) {
cancel(key);
group.onComplete();
}
}
}
@Override
public void onError(Throwable t) {
List> list = new ArrayList<>(groups.values());
groups.clear();
for (GroupedUnicast e : list) {
e.onError(t);
}
downstream.onError(t);
}
@Override
public void onComplete() {
List> list = new ArrayList<>(groups.values());
groups.clear();
for (GroupedUnicast e : list) {
e.onComplete();
}
downstream.onComplete();
}
@Override
public void dispose() {
// canceling the main source means we don't want any more groups
// but running groups still require new values
if (cancelled.compareAndSet(false, true)) {
if (decrementAndGet() == 0) {
upstream.dispose();
}
}
}
@Override
public boolean isDisposed() {
return cancelled.get();
}
public void cancel(K key) {
Object mapKey = key != null ? key : NULL_KEY;
groups.remove(mapKey);
if (decrementAndGet() == 0) {
upstream.dispose();
}
}
}
static final class GroupedUnicast extends GroupedObservable {
final State state;
public static GroupedUnicast createWith(K key, int bufferSize, GroupByObserver parent, boolean delayError) {
State state = new State<>(bufferSize, parent, key, delayError);
return new GroupedUnicast<>(key, state);
}
protected GroupedUnicast(K key, State state) {
super(key);
this.state = state;
}
@Override
protected void subscribeActual(Observer observer) {
state.subscribe(observer);
}
public void onNext(T t) {
state.onNext(t);
}
public void onError(Throwable e) {
state.onError(e);
}
public void onComplete() {
state.onComplete();
}
}
static final class State extends AtomicInteger implements Disposable, ObservableSource {
private static final long serialVersionUID = -3852313036005250360L;
final K key;
final SpscLinkedArrayQueue queue;
final GroupByObserver parent;
final boolean delayError;
volatile boolean done;
Throwable error;
final AtomicBoolean cancelled = new AtomicBoolean();
final AtomicReference> actual = new AtomicReference<>();
final AtomicInteger once = new AtomicInteger();
static final int FRESH = 0;
static final int HAS_SUBSCRIBER = 1;
static final int ABANDONED = 2;
static final int ABANDONED_HAS_SUBSCRIBER = ABANDONED | HAS_SUBSCRIBER;
State(int bufferSize, GroupByObserver parent, K key, boolean delayError) {
this.queue = new SpscLinkedArrayQueue<>(bufferSize);
this.parent = parent;
this.key = key;
this.delayError = delayError;
}
@Override
public void dispose() {
if (cancelled.compareAndSet(false, true)) {
if (getAndIncrement() == 0) {
actual.lazySet(null);
cancelParent();
}
}
}
@Override
public boolean isDisposed() {
return cancelled.get();
}
@Override
public void subscribe(Observer observer) {
for (;;) {
int s = once.get();
if ((s & HAS_SUBSCRIBER) != 0) {
break;
}
int u = s | HAS_SUBSCRIBER;
if (once.compareAndSet(s, u)) {
observer.onSubscribe(this);
actual.lazySet(observer);
if (cancelled.get()) {
actual.lazySet(null);
} else {
drain();
}
return;
}
}
EmptyDisposable.error(new IllegalStateException("Only one Observer allowed!"), observer);
}
public void onNext(T t) {
queue.offer(t);
drain();
}
public void onError(Throwable e) {
error = e;
done = true;
drain();
}
public void onComplete() {
done = true;
drain();
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
int missed = 1;
final SpscLinkedArrayQueue q = queue;
final boolean delayError = this.delayError;
Observer a = actual.get();
for (;;) {
if (a != null) {
for (;;) {
boolean d = done;
T v = q.poll();
boolean empty = v == null;
if (checkTerminated(d, empty, a, delayError)) {
return;
}
if (empty) {
break;
}
a.onNext(v);
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
if (a == null) {
a = actual.get();
}
}
}
void cancelParent() {
if ((once.get() & ABANDONED) == 0) {
parent.cancel(key);
}
}
boolean tryAbandon() {
return once.get() == FRESH && once.compareAndSet(FRESH, ABANDONED);
}
boolean checkTerminated(boolean d, boolean empty, Observer a, boolean delayError) {
if (cancelled.get()) {
queue.clear();
actual.lazySet(null);
cancelParent();
return true;
}
if (d) {
if (delayError) {
if (empty) {
Throwable e = error;
actual.lazySet(null);
if (e != null) {
a.onError(e);
} else {
a.onComplete();
}
return true;
}
} else {
Throwable e = error;
if (e != null) {
queue.clear();
actual.lazySet(null);
a.onError(e);
return true;
} else
if (empty) {
actual.lazySet(null);
a.onComplete();
return true;
}
}
}
return false;
}
}
}
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