/*
* 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.
Objects;
import java.util.concurrent.
Callable;
import java.util.concurrent.atomic.
AtomicReferenceFieldUpdater;
import java.util.function.
Function;
import java.util.stream.
Stream;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Fuseable;
import reactor.core.
Scannable;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Given a Mono source, applies a function on its single item and continues
* with that Mono instance, emitting its final result.
*
* @param <T> the value type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
MonoFlatMap<T, R> extends
MonoOperator<T, R> implements
Fuseable {
final
Function<? super T, ? extends
Mono<? extends R>>
mapper;
MonoFlatMap(
Mono<? extends T>
source,
Function<? super T, ? extends
Mono<? extends R>>
mapper) {
super(
source);
this.
mapper =
Objects.
requireNonNull(
mapper, "mapper");
}
@
Override
public void
subscribe(
CoreSubscriber<? super R>
actual) {
if (
FluxFlatMap.
trySubscribeScalarMap(
source,
actual,
mapper, true)) {
return;
}
FlatMapMain<T, R>
manager = new
FlatMapMain<>(
actual,
mapper);
actual.
onSubscribe(
manager);
source.
subscribe(
manager);
}
static final class
FlatMapMain<T, R> extends
Operators.
MonoSubscriber<T, R> {
final
Function<? super T, ? extends
Mono<? extends R>>
mapper;
final
FlatMapInner<R>
second;
boolean
done;
volatile
Subscription s;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
FlatMapMain,
Subscription>
S =
AtomicReferenceFieldUpdater.
newUpdater(
FlatMapMain.class,
Subscription.class,
"s");
FlatMapMain(
CoreSubscriber<? super R>
subscriber,
Function<? super T, ? extends
Mono<? extends R>>
mapper) {
super(
subscriber);
this.
mapper =
mapper;
this.
second = new
FlatMapInner<>(this);
}
@
Override
public
Stream<? extends
Scannable>
inners() {
return
Stream.
of(
second);
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
CANCELLED) return
s ==
Operators.
cancelledSubscription();
if (
key ==
Attr.
TERMINATED) return
done;
return super.scanUnsafe(
key);
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
setOnce(
S, this,
s)) {
s.
request(
Long.
MAX_VALUE);
}
}
@
Override
public void
onNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t,
actual.
currentContext());
return;
}
done = true;
Mono<? extends R>
m;
try {
m =
Objects.
requireNonNull(
mapper.
apply(
t),
"The mapper returned a null Mono");
}
catch (
Throwable ex) {
actual.
onError(
Operators.
onOperatorError(
s,
ex,
t,
actual.
currentContext()));
return;
}
if (
m instanceof
Callable) {
@
SuppressWarnings("unchecked")
Callable<R>
c = (
Callable<R>)
m;
R
v;
try {
v =
c.
call();
}
catch (
Throwable ex) {
actual.
onError(
Operators.
onOperatorError(
s,
ex,
t,
actual.
currentContext()));
return;
}
if (
v == null) {
actual.
onComplete();
}
else {
complete(
v);
}
return;
}
try {
m.
subscribe(
second);
}
catch (
Throwable e) {
actual.
onError(
Operators.
onOperatorError(this,
e,
t,
actual.
currentContext()));
}
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t,
actual.
currentContext());
return;
}
done = true;
actual.
onError(
t);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
actual.
onComplete();
}
@
Override
public void
cancel() {
super.cancel();
Operators.
terminate(
S, this);
second.
cancel();
}
void
secondError(
Throwable ex) {
actual.
onError(
ex);
}
void
secondComplete() {
actual.
onComplete();
}
}
static final class
FlatMapInner<R> implements
InnerConsumer<R> {
final
FlatMapMain<?, R>
parent;
volatile
Subscription s;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
FlatMapInner,
Subscription>
S =
AtomicReferenceFieldUpdater.
newUpdater(
FlatMapInner.class,
Subscription.class,
"s");
boolean
done;
FlatMapInner(
FlatMapMain<?, R>
parent) {
this.
parent =
parent;
}
@
Override
public
Context currentContext() {
return
parent.
currentContext();
}
@
Nullable
@
Override
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
ACTUAL) return
parent;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
CANCELLED) return
s ==
Operators.
cancelledSubscription();
return null;
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
setOnce(
S, this,
s)) {
s.
request(
Long.
MAX_VALUE);
}
}
@
Override
public void
onNext(R
t) {
if (
done) {
Operators.
onNextDropped(
t,
parent.
currentContext());
return;
}
done = true;
this.
parent.
complete(
t);
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t,
parent.
currentContext());
return;
}
done = true;
this.
parent.
secondError(
t);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
this.
parent.
secondComplete();
}
void
cancel() {
Operators.
terminate(
S, this);
}
}
}