/*
* Copyright (c) 2011-2017 Pivotal Software Inc, All Rights Reserved.
*
* 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 reactor.core.publisher;
import java.util.
Map;
import java.util.
Objects;
import java.util.
Queue;
import java.util.concurrent.
ConcurrentHashMap;
import java.util.concurrent.atomic.
AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.
AtomicLongFieldUpdater;
import java.util.concurrent.atomic.
AtomicReferenceFieldUpdater;
import java.util.function.
Function;
import java.util.function.
Supplier;
import java.util.stream.
Stream;
import org.reactivestreams.
Subscriber;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Exceptions;
import reactor.core.
Fuseable;
import reactor.core.
Scannable;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Groups upstream items into their own Publisher sequence based on a key selector.
*
* @param <T> the source value type
* @param <K> the key value type
* @param <V> the group item value type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxGroupBy<T, K, V> extends
FluxOperator<T,
GroupedFlux<K, V>>
implements
Fuseable {
final
Function<? super T, ? extends K>
keySelector;
final
Function<? super T, ? extends V>
valueSelector;
final
Supplier<? extends
Queue<V>>
groupQueueSupplier;
final
Supplier<? extends
Queue<
GroupedFlux<K, V>>>
mainQueueSupplier;
final int
prefetch;
FluxGroupBy(
Flux<? extends T>
source,
Function<? super T, ? extends K>
keySelector,
Function<? super T, ? extends V>
valueSelector,
Supplier<? extends
Queue<
GroupedFlux<K, V>>>
mainQueueSupplier,
Supplier<? extends
Queue<V>>
groupQueueSupplier,
int
prefetch) {
super(
source);
if (
prefetch <= 0) {
throw new
IllegalArgumentException("prefetch > 0 required but it was " +
prefetch);
}
this.
keySelector =
Objects.
requireNonNull(
keySelector, "keySelector");
this.
valueSelector =
Objects.
requireNonNull(
valueSelector, "valueSelector");
this.
mainQueueSupplier =
Objects.
requireNonNull(
mainQueueSupplier, "mainQueueSupplier");
this.
groupQueueSupplier =
Objects.
requireNonNull(
groupQueueSupplier, "groupQueueSupplier");
this.
prefetch =
prefetch;
}
@
Override
public void
subscribe(
CoreSubscriber<? super
GroupedFlux<K, V>>
actual) {
source.
subscribe(new
GroupByMain<>(
actual,
mainQueueSupplier.
get(),
groupQueueSupplier,
prefetch,
keySelector,
valueSelector));
}
@
Override
public int
getPrefetch() {
return
prefetch;
}
static final class
GroupByMain<T, K, V>
implements
QueueSubscription<
GroupedFlux<K, V>>,
InnerOperator<T,
GroupedFlux<K, V>> {
final
Function<? super T, ? extends K>
keySelector;
final
Function<? super T, ? extends V>
valueSelector;
final
Queue<
GroupedFlux<K, V>>
queue;
final
Supplier<? extends
Queue<V>>
groupQueueSupplier;
final int
prefetch;
final
Map<K,
UnicastGroupedFlux<K, V>>
groupMap;
final
CoreSubscriber<? super
GroupedFlux<K, V>>
actual;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
GroupByMain>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
GroupByMain.class, "wip");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
GroupByMain>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
GroupByMain.class, "requested");
volatile boolean
done;
volatile
Throwable error;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
GroupByMain,
Throwable>
ERROR =
AtomicReferenceFieldUpdater.
newUpdater(
GroupByMain.class,
Throwable.class,
"error");
volatile int
cancelled;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
GroupByMain>
CANCELLED =
AtomicIntegerFieldUpdater.
newUpdater(
GroupByMain.class, "cancelled");
volatile int
groupCount;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
GroupByMain>
GROUP_COUNT =
AtomicIntegerFieldUpdater.
newUpdater(
GroupByMain.class, "groupCount");
Subscription s;
volatile boolean
enableAsyncFusion;
GroupByMain(
CoreSubscriber<? super
GroupedFlux<K, V>>
actual,
Queue<
GroupedFlux<K, V>>
queue,
Supplier<? extends
Queue<V>>
groupQueueSupplier,
int
prefetch,
Function<? super T, ? extends K>
keySelector,
Function<? super T, ? extends V>
valueSelector) {
this.
actual =
actual;
this.
queue =
queue;
this.
groupQueueSupplier =
groupQueueSupplier;
this.
prefetch =
prefetch;
this.
groupMap = new
ConcurrentHashMap<>();
this.
keySelector =
keySelector;
this.
valueSelector =
valueSelector;
GROUP_COUNT.
lazySet(this, 1);
}
@
Override
public final
CoreSubscriber<? super
GroupedFlux<K, V>>
actual() {
return
actual;
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
s.
request(
Operators.
unboundedOrPrefetch(
prefetch));
}
}
@
Override
public void
onNext(T
t) {
if(
done){
Operators.
onNextDropped(
t,
actual.
currentContext());
return;
}
K
key;
V
value;
try {
key =
Objects.
requireNonNull(
keySelector.
apply(
t), "The keySelector returned a null value");
value =
Objects.
requireNonNull(
valueSelector.
apply(
t), "The valueSelector returned a null value");
}
catch (
Throwable ex) {
onError(
Operators.
onOperatorError(
s,
ex,
t,
actual.
currentContext()));
return;
}
UnicastGroupedFlux<K, V>
g =
groupMap.
get(
key);
if (
g == null) {
// if the main is cancelled, don't create new groups
if (
cancelled == 0) {
Queue<V>
q =
groupQueueSupplier.
get();
GROUP_COUNT.
getAndIncrement(this);
g = new
UnicastGroupedFlux<>(
key,
q, this,
prefetch);
g.
onNext(
value);
groupMap.
put(
key,
g);
queue.
offer(
g);
drain();
}
}
else {
g.
onNext(
value);
}
}
@
Override
public void
onError(
Throwable t) {
if (
Exceptions.
addThrowable(
ERROR, this,
t)) {
done = true;
drain();
}
else {
Operators.
onErrorDropped(
t,
actual.
currentContext());
}
}
@
Override
public void
onComplete() {
if(
done){
return;
}
for (
UnicastGroupedFlux<K, V>
g :
groupMap.
values()) {
g.
onComplete();
}
groupMap.
clear();
done = true;
drain();
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) return
requested;
if (
key ==
Attr.
PREFETCH) return
prefetch;
if (
key ==
Attr.
BUFFERED) return
queue.
size();
if (
key ==
Attr.
CANCELLED) return
cancelled == 1;
if (
key ==
Attr.
ERROR) return
error;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
Stream<? extends
Scannable>
inners() {
return
groupMap.
values().
stream();
}
void
signalAsyncError() {
Throwable e =
Exceptions.
terminate(
ERROR, this); //TODO investigate if e == null
if (
e == null) {
e = new
IllegalStateException("FluxGroupBy.signalAsyncError called without error set");
}
groupCount = 0;
for (
UnicastGroupedFlux<K, V>
g :
groupMap.
values()) {
g.
onError(
e);
}
actual.
onError(
e);
groupMap.
clear();
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
Operators.
addCap(
REQUESTED, this,
n);
drain();
}
}
@
Override
public void
cancel() {
if (
CANCELLED.
compareAndSet(this, 0, 1)) {
if (
GROUP_COUNT.
decrementAndGet(this) == 0) {
s.
cancel();
}
else if (!
enableAsyncFusion) {
if (
WIP.
getAndIncrement(this) == 0) {
// remove queued up but unobservable groups from the mapping
GroupedFlux<K, V>
g;
while ((
g =
queue.
poll()) != null) {
((
UnicastGroupedFlux<K, V>)
g).
cancel();
}
if (
WIP.
decrementAndGet(this) == 0) {
return;
}
drainLoop();
}
}
}
}
void
groupTerminated(K
key) {
if (
groupCount == 0) {
return;
}
groupMap.
remove(
key);
if (
GROUP_COUNT.
decrementAndGet(this) == 0) {
s.
cancel();
}
}
void
drain() {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
if (
enableAsyncFusion) {
drainFused();
}
else {
drainLoop();
}
}
void
drainFused() {
int
missed = 1;
final
Subscriber<? super
GroupedFlux<K, V>>
a =
actual;
final
Queue<
GroupedFlux<K, V>>
q =
queue;
for (; ; ) {
if (
cancelled != 0) {
q.
clear();
return;
}
boolean
d =
done;
a.
onNext(null);
if (
d) {
Throwable ex =
error;
if (
ex != null) {
signalAsyncError();
}
else {
a.
onComplete();
}
return;
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
void
drainLoop() {
int
missed = 1;
Subscriber<? super
GroupedFlux<K, V>>
a =
actual;
Queue<
GroupedFlux<K, V>>
q =
queue;
for (; ; ) {
long
r =
requested;
long
e = 0L;
while (
e !=
r) {
boolean
d =
done;
GroupedFlux<K, V>
v =
q.
poll();
boolean
empty =
v == null;
if (
checkTerminated(
d,
empty,
a,
q)) {
return;
}
if (
empty) {
break;
}
a.
onNext(
v);
e++;
}
if (
e ==
r) {
if (
checkTerminated(
done,
q.
isEmpty(),
a,
q)) {
return;
}
}
if (
e != 0L) {
s.
request(
e);
if (
r !=
Long.
MAX_VALUE) {
REQUESTED.
addAndGet(this, -
e);
}
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
boolean
checkTerminated(boolean
d,
boolean
empty,
Subscriber<?>
a,
Queue<
GroupedFlux<K, V>>
q) {
if (
d) {
Throwable e =
error;
if (
e != null &&
e !=
Exceptions.
TERMINATED) {
q.
clear();
signalAsyncError();
return true;
}
else if (
empty) {
a.
onComplete();
return true;
}
}
return false;
}
@
Override
@
Nullable
public
GroupedFlux<K, V>
poll() {
return
queue.
poll();
}
@
Override
public int
size() {
return
queue.
size();
}
@
Override
public boolean
isEmpty() {
return
queue.
isEmpty();
}
@
Override
public void
clear() {
queue.
clear();
}
@
Override
public int
requestFusion(int
requestedMode) {
if ((
requestedMode &
Fuseable.
ASYNC) != 0) {
enableAsyncFusion = true;
return
Fuseable.
ASYNC;
}
return
Fuseable.
NONE;
}
}
static final class
UnicastGroupedFlux<K, V> extends
GroupedFlux<K, V>
implements
Fuseable,
QueueSubscription<V>,
InnerProducer<V> {
final K
key;
final int
limit;
final
Context context;
@
Override
public K
key() {
return
key;
}
final
Queue<V>
queue;
volatile
GroupByMain<?, K, V>
parent;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
UnicastGroupedFlux,
GroupByMain>
PARENT =
AtomicReferenceFieldUpdater.
newUpdater(
UnicastGroupedFlux.class,
GroupByMain.class,
"parent");
volatile boolean
done;
Throwable error;
volatile
CoreSubscriber<? super V>
actual;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
UnicastGroupedFlux,
CoreSubscriber>
ACTUAL =
AtomicReferenceFieldUpdater.
newUpdater(
UnicastGroupedFlux.class,
CoreSubscriber.class,
"actual");
volatile boolean
cancelled;
volatile int
once;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
UnicastGroupedFlux>
ONCE =
AtomicIntegerFieldUpdater.
newUpdater(
UnicastGroupedFlux.class, "once");
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
UnicastGroupedFlux>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
UnicastGroupedFlux.class, "wip");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
UnicastGroupedFlux>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
UnicastGroupedFlux.class, "requested");
volatile boolean
outputFused;
int
produced;
UnicastGroupedFlux(K
key,
Queue<V>
queue,
GroupByMain<?, K, V>
parent,
int
prefetch) {
this.
key =
key;
this.
queue =
queue;
this.
context =
parent.
currentContext();
this.
parent =
parent;
this.
limit =
Operators.
unboundedOrLimit(
prefetch);
}
void
doTerminate() {
GroupByMain<?, K, V>
r =
parent;
if (
r != null &&
PARENT.
compareAndSet(this,
r, null)) {
r.
groupTerminated(
key);
}
}
void
drainRegular(
Subscriber<? super V>
a) {
int
missed = 1;
final
Queue<V>
q =
queue;
for (; ; ) {
long
r =
requested;
long
e = 0L;
while (
r !=
e) {
boolean
d =
done;
V
t =
q.
poll();
boolean
empty =
t == null;
if (
checkTerminated(
d,
empty,
a,
q)) {
return;
}
if (
empty) {
break;
}
a.
onNext(
t);
e++;
}
if (
r ==
e) {
if (
checkTerminated(
done,
q.
isEmpty(),
a,
q)) {
return;
}
}
if (
e != 0) {
GroupByMain<?, K, V>
main =
parent;
if (
main != null) {
main.
s.
request(
e);
}
if (
r !=
Long.
MAX_VALUE) {
REQUESTED.
addAndGet(this, -
e);
}
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
void
drainFused(
Subscriber<? super V>
a) {
int
missed = 1;
final
Queue<V>
q =
queue;
for (; ; ) {
if (
cancelled) {
q.
clear();
actual = null;
return;
}
boolean
d =
done;
a.
onNext(null);
if (
d) {
actual = null;
Throwable ex =
error;
if (
ex != null) {
a.
onError(
ex);
}
else {
a.
onComplete();
}
return;
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
void
drain() {
Subscriber<? super V>
a =
actual;
if (
a != null) {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
if (
outputFused) {
drainFused(
a);
}
else {
drainRegular(
a);
}
}
}
boolean
checkTerminated(boolean
d, boolean
empty,
Subscriber<?>
a,
Queue<?>
q) {
if (
cancelled) {
q.
clear();
actual = null;
return true;
}
if (
d &&
empty) {
Throwable e =
error;
actual = null;
if (
e != null) {
a.
onError(
e);
}
else {
a.
onComplete();
}
return true;
}
return false;
}
public void
onNext(V
t) {
Subscriber<? super V>
a =
actual;
if (!
queue.
offer(
t)) {
onError(
Operators.
onOperatorError(this,
Exceptions.
failWithOverflow(
Exceptions.
BACKPRESSURE_ERROR_QUEUE_FULL),
t,
actual.
currentContext()));
return;
}
if (
outputFused) {
if (
a != null) {
a.
onNext(null); // in op-fusion, onNext(null) is the indicator of more data
}
}
else {
drain();
}
}
public void
onError(
Throwable t) {
error =
t;
done = true;
doTerminate();
drain();
}
public void
onComplete() {
done = true;
doTerminate();
drain();
}
@
Override
public void
subscribe(
CoreSubscriber<? super V>
actual) {
if (
once == 0 &&
ONCE.
compareAndSet(this, 0, 1)) {
actual.
onSubscribe(this);
ACTUAL.
lazySet(this,
actual);
drain();
}
else {
actual.
onError(new
IllegalStateException(
"GroupedFlux allows only one Subscriber"));
}
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
Operators.
addCap(
REQUESTED, this,
n);
drain();
}
}
@
Override
public void
cancel() {
if (
cancelled) {
return;
}
cancelled = true;
doTerminate();
if (!
outputFused) {
if (
WIP.
getAndIncrement(this) == 0) {
queue.
clear();
}
}
}
@
Override
@
Nullable
public V
poll() {
V
v =
queue.
poll();
if (
v != null) {
produced++;
}
else {
int
p =
produced;
if (
p != 0) {
produced = 0;
GroupByMain<?, K, V>
main =
parent;
if (
main != null) {
main.
s.
request(
p);
}
}
}
return
v;
}
@
Override
public int
size() {
return
queue.
size();
}
@
Override
public boolean
isEmpty() {
return
queue.
isEmpty();
}
@
Override
public void
clear() {
queue.
clear();
}
@
Override
public int
requestFusion(int
requestedMode) {
if ((
requestedMode &
Fuseable.
ASYNC) != 0) {
outputFused = true;
return
Fuseable.
ASYNC;
}
return
Fuseable.
NONE;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
parent;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
CANCELLED) return
cancelled;
if (
key ==
Attr.
ERROR) return
error;
if (
key ==
Attr.
BUFFERED) return
queue != null ?
queue.
size() : 0;
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) return
requested;
return
InnerProducer.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super V>
actual() {
return
actual;
}
}
}