rx.internal.operators.OperatorMapNotification 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.concurrent.atomic.*;
import rx.*;
import rx.Observable.Operator;
import rx.exceptions.Exceptions;
import rx.functions.*;
/**
* Applies a function of your choosing to every item emitted by an {@code Observable}, and emits the results of
* this transformation as a new {@code Observable}.
*
* 
* @param the input value type
* @param the output value type
*/
public final class OperatorMapNotification implements Operator {
final Func1 onNext;
final Func1 onError;
final Func0 onCompleted;
public OperatorMapNotification(Func1 onNext, Func1 onError, Func0 onCompleted) {
this.onNext = onNext;
this.onError = onError;
this.onCompleted = onCompleted;
}
@Override
public Subscriber call(final Subscriber child) {
final MapNotificationSubscriber parent = new MapNotificationSubscriber(child, onNext, onError, onCompleted);
child.add(parent);
child.setProducer(new Producer() {
@Override
public void request(long n) {
parent.requestInner(n);
}
});
return parent;
}
static final class MapNotificationSubscriber extends Subscriber {
final Subscriber actual;
final Func1 onNext;
final Func1 onError;
final Func0 onCompleted;
final AtomicLong requested;
final AtomicLong missedRequested;
final AtomicReference producer;
long produced;
R value;
static final long COMPLETED_FLAG = Long.MIN_VALUE;
static final long REQUESTED_MASK = Long.MAX_VALUE;
public MapNotificationSubscriber(Subscriber actual, Func1 onNext,
Func1 onError, Func0 onCompleted) {
this.actual = actual;
this.onNext = onNext;
this.onError = onError;
this.onCompleted = onCompleted;
this.requested = new AtomicLong();
this.missedRequested = new AtomicLong();
this.producer = new AtomicReference();
}
@Override
public void onNext(T t) {
try {
produced++;
actual.onNext(onNext.call(t));
} catch (Throwable ex) {
Exceptions.throwOrReport(ex, actual, t);
}
}
@Override
public void onError(Throwable e) {
accountProduced();
try {
value = onError.call(e);
} catch (Throwable ex) {
Exceptions.throwOrReport(ex, actual, e);
}
tryEmit();
}
@Override
public void onCompleted() {
accountProduced();
try {
value = onCompleted.call();
} catch (Throwable ex) {
Exceptions.throwOrReport(ex, actual);
}
tryEmit();
}
void accountProduced() {
long p = produced;
if (p != 0L && producer.get() != null) {
BackpressureUtils.produced(requested, p);
}
}
@Override
public void setProducer(Producer p) {
if (producer.compareAndSet(null, p)) {
long r = missedRequested.getAndSet(0L);
if (r != 0L) {
p.request(r);
}
} else {
throw new IllegalStateException("Producer already set!");
}
}
void tryEmit() {
for (;;) {
long r = requested.get();
if ((r & COMPLETED_FLAG) != 0) {
break;
}
if (requested.compareAndSet(r, r | COMPLETED_FLAG)) {
if (r != 0 || producer.get() == null) {
if (!actual.isUnsubscribed()) {
actual.onNext(value);
}
if (!actual.isUnsubscribed()) {
actual.onCompleted();
}
}
return;
}
}
}
void requestInner(long n) {
if (n < 0L) {
throw new IllegalArgumentException("n >= 0 required but it was " + n);
}
if (n == 0L) {
return;
}
for (;;) {
long r = requested.get();
if ((r & COMPLETED_FLAG) != 0L) {
long v = r & REQUESTED_MASK;
long u = BackpressureUtils.addCap(v, n) | COMPLETED_FLAG;
if (requested.compareAndSet(r, u)) {
if (v == 0L) {
if (!actual.isUnsubscribed()) {
actual.onNext(value);
}
if (!actual.isUnsubscribed()) {
actual.onCompleted();
}
}
return;
}
} else {
long u = BackpressureUtils.addCap(r, n);
if (requested.compareAndSet(r, u)) {
break;
}
}
}
AtomicReference localProducer = producer;
Producer actualProducer = localProducer.get();
if (actualProducer != null) {
actualProducer.request(n);
} else {
BackpressureUtils.getAndAddRequest(missedRequested, n);
actualProducer = localProducer.get();
if (actualProducer != null) {
long r = missedRequested.getAndSet(0L);
if (r != 0L) {
actualProducer.request(r);
}
}
}
}
}
}