/*
* 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.AbstractQueue;
import java.util.Iterator;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.function.BooleanSupplier;
import java.util.function.Function;
import java.util.function.Supplier;
import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
/**
* Maps the values of the source publisher one-on-one via a mapper function.
*
* @param <T> the source value type
* @param <R> the result value type
* @author Stephane Maldini
*/
final class FluxMapSignal<T, R> extends FluxSource<T, R> {
final Function<? super T, ? extends R> mapperNext;
final Function<? super Throwable, ? extends R> mapperError;
final Supplier<? extends R> mapperComplete;
/**
* Constructs a FluxMapSignal instance with the given source and mappers.
*
* @param source the source Publisher instance
* @param mapperNext the next mapper function
* @param mapperError the error mapper function
* @param mapperComplete the complete mapper function
*
* @throws NullPointerException if either {@code source} or {@code mapper} is null.
*/
FluxMapSignal(Publisher<? extends T> source,
Function<? super T, ? extends R> mapperNext,
Function<? super Throwable, ? extends R> mapperError,
Supplier<? extends R> mapperComplete) {
super(source);
if(mapperNext == null && mapperError == null && mapperComplete == null){
throw new IllegalArgumentException("Map Signal needs at least one valid mapper");
}
this.mapperNext = mapperNext;
this.mapperError = mapperError;
this.mapperComplete = mapperComplete;
}
@Override
public void subscribe(Subscriber<? super R> s) {
source.subscribe(new FluxMapSignalSubscriber<>(s, this));
}
static final class FluxMapSignalSubscriber<T, R>
extends AbstractQueue<R>
implements InnerOperator<T, R>,
BooleanSupplier {
final Subscriber<? super R> actual;
final FluxMapSignal<T, R> parent;
boolean done;
Subscription s;
R value;
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater<FluxMapSignalSubscriber> REQUESTED =
AtomicLongFieldUpdater.newUpdater(FluxMapSignalSubscriber.class, "requested");
volatile boolean cancelled;
long produced;
FluxMapSignalSubscriber(Subscriber<? super R> actual, FluxMapSignal<T, R> parent) {
this.actual = actual;
this.parent = parent;
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.s, s)) {
this.s = s;
actual.onSubscribe(this);
if (parent.mapperNext == null) {
s.request(Long.MAX_VALUE);
}
}
}
@Override
public void onNext(T t) {
if (done) {
Operators.onNextDropped(t);
return;
}
if (parent.mapperNext == null) {
return;
}
R v;
try {
v = Objects.requireNonNull(parent.mapperNext.apply(t),
"The mapper returned a null value.");
}
catch (Throwable e) {
done = true;
actual.onError(Operators.onOperatorError(s, e, t));
return;
}
produced++;
actual.onNext(v);
}
@Override
public void onError(Throwable t) {
if (done) {
Operators.onErrorDropped(t);
return;
}
done = true;
if(parent.mapperError == null){
actual.onError(t);
return;
}
R v;
try {
v = Objects.requireNonNull(parent.mapperError.apply(t),
"The mapper returned a null value.");
}
catch (Throwable e) {
done = true;
actual.onError(Operators.onOperatorError(s, e, t));
return;
}
value = v;
long p = produced;
if (p != 0L) {
Operators.addAndGet(REQUESTED, this, -p);
}
DrainUtils.postComplete(actual, this, REQUESTED, this, this);
}
@Override
public void onComplete() {
if (done) {
return;
}
done = true;
if(parent.mapperComplete == null){
actual.onComplete();
return;
}
R v;
try {
v = Objects.requireNonNull(parent.mapperComplete.get(),
"The mapper returned a null value.");
}
catch (Throwable e) {
done = true;
actual.onError(Operators.onOperatorError(s, e));
return;
}
value = v;
long p = produced;
if (p != 0L) {
Operators.addAndGet(REQUESTED, this, -p);
}
DrainUtils.postComplete(actual, this, REQUESTED, this, this);
}
@Override
public Subscriber<? super R> actual() {
return actual;
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
if (!DrainUtils.postCompleteRequest(n, actual, this, REQUESTED, this, this)) {
s.request(n);
}
}
}
@Override
public boolean offer(R e) {
throw new UnsupportedOperationException();
}
@Override
public R poll() {
R v = value;
if (v != null) {
value = null;
return v;
}
return null;
}
@Override
public Object scan(Attr key) {
switch (key) {
case PARENT:
return s;
case TERMINATED:
return done;
case CANCELLED:
return getAsBoolean();
case REQUESTED_FROM_DOWNSTREAM:
return requested;
case BUFFERED:
return size();
}
return InnerOperator.super.scan(key);
}
@Override
public R peek() {
return value;
}
@Override
public boolean getAsBoolean() {
return cancelled;
}
@Override
public void cancel() {
cancelled = true;
s.cancel();
}
@Override
public Iterator<R> iterator() {
throw new UnsupportedOperationException();
}
@Override
public int size() {
return value == null ? 0 : 1;
}
}
}