rx.internal.operators.OperatorGroupBy Maven / Gradle / Ivy
/**
* Copyright 2014 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 rx.internal.operators;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import rx.*;
import rx.Observable.*;
import rx.exceptions.Exceptions;
import rx.functions.*;
import rx.internal.producers.ProducerArbiter;
import rx.internal.util.*;
import rx.observables.GroupedObservable;
import rx.observers.Subscribers;
import rx.plugins.RxJavaHooks;
import rx.subscriptions.Subscriptions;
/**
* Groups the items emitted by an Observable according to a specified criterion, and emits these
* grouped items as Observables, one Observable per group.
*
* 
*
* @param
* the key type
* @param
* the source and group value type
* @param
* the value type of the groups
*/
public final class OperatorGroupBy implements Operator, T> {
final Func1 keySelector;
final Func1 valueSelector;
final int bufferSize;
final boolean delayError;
final Func1, Map> mapFactory;
@SuppressWarnings({ "unchecked", "rawtypes" })
public OperatorGroupBy(Func1 keySelector) {
this(keySelector, (Func1)UtilityFunctions.identity(), RxRingBuffer.SIZE, false, null);
}
public OperatorGroupBy(Func1 keySelector, Func1 valueSelector) {
this(keySelector, valueSelector, RxRingBuffer.SIZE, false, null);
}
public OperatorGroupBy(Func1 keySelector, Func1 valueSelector, Func1, Map> mapFactory) {
this(keySelector, valueSelector, RxRingBuffer.SIZE, false, mapFactory);
}
public OperatorGroupBy(Func1 keySelector, Func1 valueSelector, int bufferSize, boolean delayError, Func1, Map> mapFactory) {
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
this.mapFactory = mapFactory;
}
@Override
public Subscriber call(Subscriber> child) {
final GroupBySubscriber parent; // NOPMD
try {
parent = new GroupBySubscriber(child, keySelector, valueSelector, bufferSize, delayError, mapFactory);
} catch (Throwable ex) {
//Can reach here because mapFactory.call() may throw in constructor of GroupBySubscriber
Exceptions.throwOrReport(ex, child);
Subscriber parent2 = Subscribers.empty();
parent2.unsubscribe();
return parent2;
}
child.add(Subscriptions.create(new Action0() {
@Override
public void call() {
parent.cancel();
}
}));
child.setProducer(parent.producer);
return parent;
}
public static final class GroupByProducer implements Producer {
final GroupBySubscriber parent;
public GroupByProducer(GroupBySubscriber parent) {
this.parent = parent;
}
@Override
public void request(long n) {
parent.requestMore(n);
}
}
public static final class GroupBySubscriber
extends Subscriber {
final Subscriber> actual;
final Func1 keySelector;
final Func1 valueSelector;
final int bufferSize;
final boolean delayError;
final Map> groups;
final Queue> queue;
final GroupByProducer producer;
final Queue evictedKeys;
static final Object NULL_KEY = new Object();
final ProducerArbiter s;
final AtomicBoolean cancelled;
final AtomicLong requested;
final AtomicInteger groupCount;
Throwable error;
volatile boolean done;
final AtomicInteger wip;
public GroupBySubscriber(Subscriber> actual, Func1 keySelector,
Func1 valueSelector, int bufferSize, boolean delayError,
Func1, Map> mapFactory) {
this.actual = actual;
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
this.queue = new ConcurrentLinkedQueue>();
this.s = new ProducerArbiter();
this.s.request(bufferSize);
this.producer = new GroupByProducer(this);
this.cancelled = new AtomicBoolean();
this.requested = new AtomicLong();
this.groupCount = new AtomicInteger(1);
this.wip = new AtomicInteger();
if (mapFactory == null) {
this.groups = new ConcurrentHashMap>();
this.evictedKeys = null;
} else {
this.evictedKeys = new ConcurrentLinkedQueue();
this.groups = createMap(mapFactory, new EvictionAction(evictedKeys));
}
}
static class EvictionAction implements Action1 {
final Queue evictedKeys;
EvictionAction(Queue evictedKeys) {
this.evictedKeys = evictedKeys;
}
@Override
public void call(K key) {
evictedKeys.offer(key);
}
}
@SuppressWarnings("unchecked")
private Map> createMap(Func1, Map> mapFactory, Action1 evictionAction) {
return (Map>)(Map) mapFactory.call(evictionAction);
}
@Override
public void setProducer(Producer s) {
this.s.setProducer(s);
}
@Override
public void onNext(T t) {
if (done) {
return;
}
final Queue> q = this.queue;
final Subscriber> a = this.actual;
K key;
try {
key = keySelector.call(t);
} catch (Throwable ex) {
unsubscribe();
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.get()) {
group = GroupedUnicast.createWith(key, bufferSize, this, delayError);
groups.put(mapKey, group);
groupCount.getAndIncrement();
notNew = false;
q.offer(group);
drain();
} else {
return;
}
}
V v;
try {
v = valueSelector.call(t);
} catch (Throwable ex) {
unsubscribe();
errorAll(a, q, ex);
return;
}
group.onNext(v);
if (evictedKeys != null) {
K evictedKey;
while ((evictedKey = evictedKeys.poll()) != null) {
GroupedUnicast g = groups.get(evictedKey);
if (g != null) {
g.onComplete();
}
}
}
if (notNew) {
s.request(1);
}
}
@Override
public void onError(Throwable t) {
if (done) {
RxJavaHooks.onError(t);
return;
}
error = t;
done = true;
groupCount.decrementAndGet();
drain();
}
@Override
public void onCompleted() {
if (done) {
return;
}
for (GroupedUnicast e : groups.values()) {
e.onComplete();
}
groups.clear();
if (evictedKeys != null) {
evictedKeys.clear();
}
done = true;
groupCount.decrementAndGet();
drain();
}
public void requestMore(long n) {
if (n < 0) {
throw new IllegalArgumentException("n >= 0 required but it was " + n);
}
BackpressureUtils.getAndAddRequest(requested, n);
drain();
}
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(false, true)) {
if (groupCount.decrementAndGet() == 0) {
unsubscribe();
}
}
}
public void cancel(K key) {
Object mapKey = key != null ? key : NULL_KEY;
if (groups.remove(mapKey) != null) {
if (groupCount.decrementAndGet() == 0) {
unsubscribe();
}
}
}
void drain() {
if (wip.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.get();
long e = 0L;
while (e != r) {
boolean d = done;
GroupedObservable t = q.poll();
boolean empty = t == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
if (empty) {
break;
}
a.onNext(t);
e++;
}
if (e != 0L) {
if (r != Long.MAX_VALUE) {
BackpressureUtils.produced(requested, e);
}
s.request(e);
}
missed = wip.addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
void errorAll(Subscriber> a, Queue q, Throwable ex) {
q.clear();
List> list = new ArrayList>(groups.values());
groups.clear();
if (evictedKeys != null) {
evictedKeys.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) {
actual.onCompleted();
return true;
}
}
return false;
}
}
static final class GroupedUnicast extends GroupedObservable {
final State state;
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);
}
protected GroupedUnicast(K key, State state) {
super(key, state);
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 Producer, Subscription, OnSubscribe {
/** */
private static final long serialVersionUID = -3852313036005250360L;
final K key;
final Queue