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rxjava2-backport developed by David Karnok
/**
* Copyright 2015 David Karnok and Netflix, Inc.
*
* 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 hu.akarnokd.rxjava2.internal.operators;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import hu.akarnokd.rxjava2.Observable.Operator;
import hu.akarnokd.rxjava2.functions.Function;
import hu.akarnokd.rxjava2.internal.queue.SpscLinkedArrayQueue;
import hu.akarnokd.rxjava2.internal.subscriptions.*;
import hu.akarnokd.rxjava2.internal.util.BackpressureHelper;
import hu.akarnokd.rxjava2.observables.GroupedObservable;
import hu.akarnokd.rxjava2.plugins.RxJavaPlugins;
public final class OperatorGroupBy implements Operator, T>{
final Function keySelector;
final Function valueSelector;
final int bufferSize;
final boolean delayError;
public OperatorGroupBy(Function keySelector, Function valueSelector, int bufferSize, boolean delayError) {
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
}
@Override
public Subscriber apply(Subscriber> t) {
return new GroupBySubscriber(t, keySelector, valueSelector, bufferSize, delayError);
}
public static final class GroupBySubscriber
extends AtomicInteger
implements Subscriber, Subscription {
/** */
private static final long serialVersionUID = -3688291656102519502L;
final Subscriber> actual;
final Function keySelector;
final Function valueSelector;
final int bufferSize;
final boolean delayError;
final Map> groups;
final Queue> queue;
static final Object NULL_KEY = new Object();
Subscription s;
volatile int cancelled;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater CANCELLED =
AtomicIntegerFieldUpdater.newUpdater(GroupBySubscriber.class, "cancelled");
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(GroupBySubscriber.class, "requested");
volatile int groupCount;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater GROUP_COUNT =
AtomicIntegerFieldUpdater.newUpdater(GroupBySubscriber.class, "groupCount");
Throwable error;
volatile boolean done;
public GroupBySubscriber(Subscriber> actual, Function keySelector, Function valueSelector, int bufferSize, boolean delayError) {
this.actual = actual;
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
this.groups = new ConcurrentHashMap>();
this.queue = new SpscLinkedArrayQueue>(bufferSize);
GROUP_COUNT.lazySet(this, 1);
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validateSubscription(this.s, s)) {
return;
}
this.s = s;
actual.onSubscribe(this);
s.request(bufferSize);
}
@Override
public void onNext(T t) {
if (done) {
return;
}
final Queue> q = this.queue;
final Subscriber> a = this.actual;
K key;
try {
key = keySelector.apply(t);
} catch (Throwable ex) {
s.cancel();
errorAll(a, q, ex);
return;
}
boolean notNew = true;
Object mapKey = key != null ? key : NULL_KEY;
GroupedUnicast group = groups.get(mapKey);
if (group == null) {
// if the main has been cancelled, stop creating groups
// and skip this value
if (cancelled == 0) {
group = GroupedUnicast.createWith(key, bufferSize, this, delayError);
groups.put(mapKey, group);
GROUP_COUNT.getAndIncrement(this);
notNew = false;
q.offer(group);
drain();
} else {
return;
}
}
V v;
try {
v = valueSelector.apply(t);
} catch (Throwable ex) {
s.cancel();
errorAll(a, q, ex);
return;
}
if (v == null) {
s.cancel();
errorAll(a, q, new NullPointerException("The valueSelector returned null"));
return;
}
group.onNext(v);
if (notNew) {
s.request(1);
}
}
@Override
public void onError(Throwable t) {
if (done) {
RxJavaPlugins.onError(t);
return;
}
error = t;
done = true;
GROUP_COUNT.decrementAndGet(this);
drain();
}
@Override
public void onComplete() {
if (done) {
return;
}
done = true;
GROUP_COUNT.decrementAndGet(this);
drain();
}
@Override
public void request(long n) {
if (SubscriptionHelper.validateRequest(n)) {
return;
}
BackpressureHelper.add(REQUESTED, this, n);
drain();
}
@Override
public void cancel() {
// cancelling the main source means we don't want any more groups
// but running groups still require new values
if (CANCELLED.compareAndSet(this, 0, 1)) {
if (GROUP_COUNT.decrementAndGet(this) == 0) {
s.cancel();
}
}
}
public void cancel(K key) {
Object mapKey = key != null ? key : NULL_KEY;
groups.remove(mapKey);
if (GROUP_COUNT.decrementAndGet(this) == 0) {
s.cancel();
}
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
int missed = 1;
final Queue> q = this.queue;
final Subscriber> a = this.actual;
for (;;) {
if (checkTerminated(done, q.isEmpty(), a, q)) {
return;
}
long r = requested;
boolean unbounded = r == Long.MAX_VALUE;
long e = 0L;
while (r != 0) {
boolean d = done;
GroupedObservable t = q.poll();
boolean empty = t == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
if (empty) {
break;
}
a.onNext(t);
r--;
e--;
}
if (e != 0L) {
if (!unbounded) {
REQUESTED.addAndGet(this, e);
}
s.request(-e);
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
void errorAll(Subscriber> a, Queue q, Throwable ex) {
q.clear();
List> list = new ArrayList>(groups.values());
groups.clear();
for (GroupedUnicast e : list) {
e.onError(ex);
}
a.onError(ex);
}
boolean checkTerminated(boolean d, boolean empty,
Subscriber> a, Queue q) {
if (d) {
Throwable err = error;
if (err != null) {
errorAll(a, q, err);
return true;
} else
if (empty) {
List> list = new ArrayList>(groups.values());
groups.clear();
for (GroupedUnicast e : list) {
e.onComplete();
}
actual.onComplete();
return true;
}
}
return false;
}
}
static final class GroupedUnicast extends GroupedObservable {
public static GroupedUnicast createWith(K key, int bufferSize, GroupBySubscriber parent, boolean delayError) {
State state = new State(bufferSize, parent, key, delayError);
return new GroupedUnicast(key, state);
}
final State state;
protected GroupedUnicast(K key, State state) {
super(state, key);
this.state = state;
}
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 Subscription, Publisher {
/** */
private static final long serialVersionUID = -3852313036005250360L;
final K key;
final Queue queue;
final GroupBySubscriber parent;
final boolean delayError;
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(State.class, "requested");
volatile boolean done;
Throwable error;
volatile int cancelled;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater CANCELLED =
AtomicIntegerFieldUpdater.newUpdater(State.class, "cancelled");
volatile Subscriber actual;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater ACTUAL =
AtomicReferenceFieldUpdater.newUpdater(State.class, Subscriber.class, "actual");
volatile int once;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater ONCE =
AtomicIntegerFieldUpdater.newUpdater(State.class, "once");
public State(int bufferSize, GroupBySubscriber parent, K key, boolean delayError) {
this.queue = new SpscLinkedArrayQueue(bufferSize);
this.parent = parent;
this.key = key;
this.delayError = delayError;
}
@Override
public void request(long n) {
if (SubscriptionHelper.validateRequest(n)) {
return;
}
BackpressureHelper.add(REQUESTED, this, n);
drain();
}
@Override
public void cancel() {
if (CANCELLED.compareAndSet(this, 0, 1)) {
if (getAndIncrement() == 0) {
parent.cancel(key);
}
}
}
@Override
public void subscribe(Subscriber s) {
if (ONCE.compareAndSet(this, 0, 1)) {
s.onSubscribe(this);
ACTUAL.lazySet(this, s);
drain();
} else {
EmptySubscription.error(new IllegalStateException("Only one Subscriber allowed!"), s);
}
}
public void onNext(T t) {
if (t == null) {
error = new NullPointerException();
done = true;
} else {
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 Queue q = queue;
final boolean delayError = this.delayError;
Subscriber a = actual;
for (;;) {
if (a != null) {
if (checkTerminated(done, q.isEmpty(), a, delayError)) {
return;
}
long r = requested;
boolean unbounded = r == Long.MAX_VALUE;
long e = 0;
while (r != 0L) {
boolean d = done;
T v = q.poll();
boolean empty = v == null;
if (checkTerminated(d, empty, a, delayError)) {
return;
}
if (empty) {
break;
}
a.onNext(v);
r--;
e--;
}
if (e != 0L) {
if (!unbounded) {
REQUESTED.addAndGet(this, e);
}
parent.s.request(-e);
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
if (a == null) {
a = actual;
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber a, boolean delayError) {
if (cancelled != 0) {
queue.clear();
parent.cancel(key);
return true;
}
if (d) {
if (delayError) {
if (empty) {
Throwable e = error;
if (e != null) {
a.onError(e);
} else {
a.onComplete();
}
return true;
}
} else {
Throwable e = error;
if (e != null) {
queue.clear();
a.onError(e);
return true;
} else
if (empty) {
a.onComplete();
return true;
}
}
}
return false;
}
}
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