/*
* 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.
AtomicIntegerFieldUpdater;
import java.util.function.
Consumer;
import java.util.function.
Function;
import org.reactivestreams.
Publisher;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Exceptions;
import reactor.core.
Fuseable;
import reactor.util.annotation.
Nullable;
/**
* Uses a resource, generated by a supplier for each individual Subscriber,
* while streaming the values from a
* Publisher derived from the same resource and makes sure the resource is released
* if the sequence terminates or the Subscriber cancels.
* <p>
* <p>
* Eager resource cleanup happens just before the source termination and exceptions
* raised by the cleanup Consumer may override the terminal even. Non-eager
* cleanup will drop any exception.
*
* @param <T> the value type streamed
* @param <S> the resource type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxUsing<T, S> extends
Flux<T> implements
Fuseable,
SourceProducer<T> {
final
Callable<S>
resourceSupplier;
final
Function<? super S, ? extends
Publisher<? extends T>>
sourceFactory;
final
Consumer<? super S>
resourceCleanup;
final boolean
eager;
FluxUsing(
Callable<S>
resourceSupplier,
Function<? super S, ? extends
Publisher<? extends T>>
sourceFactory,
Consumer<? super S>
resourceCleanup,
boolean
eager) {
this.
resourceSupplier =
Objects.
requireNonNull(
resourceSupplier, "resourceSupplier");
this.
sourceFactory =
Objects.
requireNonNull(
sourceFactory, "sourceFactory");
this.
resourceCleanup =
Objects.
requireNonNull(
resourceCleanup, "resourceCleanup");
this.
eager =
eager;
}
@
Override
@
SuppressWarnings("unchecked")
public void
subscribe(
CoreSubscriber<? super T>
actual) {
S
resource;
try {
resource =
resourceSupplier.
call();
}
catch (
Throwable e) {
Operators.
error(
actual,
Operators.
onOperatorError(
e,
actual.
currentContext()));
return;
}
Publisher<? extends T>
p;
try {
p =
Objects.
requireNonNull(
sourceFactory.
apply(
resource),
"The sourceFactory returned a null value");
}
catch (
Throwable e) {
Throwable _e =
Operators.
onOperatorError(
e,
actual.
currentContext());
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable ex) {
_e =
Exceptions.
addSuppressed(
ex,
_e);
}
Operators.
error(
actual,
_e);
return;
}
if (
p instanceof
Fuseable) {
from(
p).
subscribe(new
UsingFuseableSubscriber<>(
actual,
resourceCleanup,
resource,
eager));
}
else if (
actual instanceof
ConditionalSubscriber) {
from(
p).
subscribe(new
UsingConditionalSubscriber<>((
ConditionalSubscriber<? super T>)
actual,
resourceCleanup,
resource,
eager));
}
else {
from(
p).
subscribe(new
UsingSubscriber<>(
actual,
resourceCleanup,
resource,
eager));
}
}
@
Override
public
Object scanUnsafe(
Attr key) {
return null; //no particular key to be represented, still useful in hooks
}
static final class
UsingSubscriber<T, S>
implements
InnerOperator<T, T>,
QueueSubscription<T> {
final
CoreSubscriber<? super T>
actual;
final
Consumer<? super S>
resourceCleanup;
final S
resource;
final boolean
eager;
Subscription s;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
UsingSubscriber>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
UsingSubscriber.class, "wip");
UsingSubscriber(
CoreSubscriber<? super T>
actual,
Consumer<? super S>
resourceCleanup,
S
resource,
boolean
eager) {
this.
actual =
actual;
this.
resourceCleanup =
resourceCleanup;
this.
resource =
resource;
this.
eager =
eager;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
TERMINATED ||
key ==
Attr.
CANCELLED) return
wip == 1;
if (
key ==
Attr.
PARENT) return
s;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
public void
request(long
n) {
s.
request(
n);
}
@
Override
public void
cancel() {
if (
WIP.
compareAndSet(this, 0, 1)) {
s.
cancel();
cleanup();
}
}
void
cleanup() {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
Operators.
onErrorDropped(
e,
actual.
currentContext());
}
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
actual.
onNext(
t);
}
@
Override
public void
onError(
Throwable t) {
if (
eager &&
WIP.
compareAndSet(this, 0, 1)) {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
Throwable _e =
Operators.
onOperatorError(
e,
actual.
currentContext());
t =
Exceptions.
addSuppressed(
_e,
t);
}
}
actual.
onError(
t);
if (!
eager &&
WIP.
compareAndSet(this, 0, 1)) {
cleanup();
}
}
@
Override
public void
onComplete() {
if (
eager &&
WIP.
compareAndSet(this, 0, 1)) {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
actual.
onError(
Operators.
onOperatorError(
e,
actual.
currentContext()));
return;
}
}
actual.
onComplete();
if (!
eager &&
WIP.
compareAndSet(this, 0, 1)) {
cleanup();
}
}
@
Override
public int
requestFusion(int
requestedMode) {
return
NONE; // always reject, upstream turned out to be non-fuseable after all
}
@
Override
public void
clear() {
// ignoring fusion methods
}
@
Override
public boolean
isEmpty() {
// ignoring fusion methods
return true;
}
@
Override
@
Nullable
public T
poll() {
return null;
}
@
Override
public int
size() {
return 0;
}
}
static final class
UsingFuseableSubscriber<T, S>
implements
InnerOperator<T, T>,
QueueSubscription<T> {
final
CoreSubscriber<? super T>
actual;
final
Consumer<? super S>
resourceCleanup;
final S
resource;
final boolean
eager;
QueueSubscription<T>
s;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
UsingFuseableSubscriber>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
UsingFuseableSubscriber.class,
"wip");
int
mode;
UsingFuseableSubscriber(
CoreSubscriber<? super T>
actual,
Consumer<? super S>
resourceCleanup,
S
resource,
boolean
eager) {
this.
actual =
actual;
this.
resourceCleanup =
resourceCleanup;
this.
resource =
resource;
this.
eager =
eager;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
TERMINATED ||
key ==
Attr.
CANCELLED)
return
wip == 1;
if (
key ==
Attr.
PARENT) return
s;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
public void
request(long
n) {
s.
request(
n);
}
@
Override
public void
cancel() {
if (
WIP.
compareAndSet(this, 0, 1)) {
s.
cancel();
cleanup();
}
}
void
cleanup() {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
Operators.
onErrorDropped(
e,
actual.
currentContext());
}
}
@
SuppressWarnings("unchecked")
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s = (
QueueSubscription<T>)
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
actual.
onNext(
t);
}
@
Override
public void
onError(
Throwable t) {
if (
eager &&
WIP.
compareAndSet(this, 0, 1)) {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
Throwable _e =
Operators.
onOperatorError(
e,
actual.
currentContext());
t =
Exceptions.
addSuppressed(
_e,
t);
}
}
actual.
onError(
t);
if (!
eager &&
WIP.
compareAndSet(this, 0, 1)) {
cleanup();
}
}
@
Override
public void
onComplete() {
if (
eager &&
WIP.
compareAndSet(this, 0, 1)) {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
actual.
onError(
Operators.
onOperatorError(
e,
actual.
currentContext()));
return;
}
}
actual.
onComplete();
if (!
eager &&
WIP.
compareAndSet(this, 0, 1)) {
cleanup();
}
}
@
Override
public void
clear() {
s.
clear();
}
@
Override
public boolean
isEmpty() {
return
s.
isEmpty();
}
@
Override
@
Nullable
public T
poll() {
T
v =
s.
poll();
if (
v == null &&
mode ==
SYNC) {
if (
WIP.
compareAndSet(this, 0, 1)) {
resourceCleanup.
accept(
resource);
}
}
return
v;
}
@
Override
public int
requestFusion(int
requestedMode) {
int
m =
s.
requestFusion(
requestedMode);
mode =
m;
return
m;
}
@
Override
public int
size() {
return
s.
size();
}
}
static final class
UsingConditionalSubscriber<T, S>
implements
ConditionalSubscriber<T>,
InnerOperator<T, T>,
QueueSubscription<T> {
final
ConditionalSubscriber<? super T>
actual;
final
Consumer<? super S>
resourceCleanup;
final S
resource;
final boolean
eager;
Subscription s;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
UsingConditionalSubscriber>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
UsingConditionalSubscriber.class,
"wip");
UsingConditionalSubscriber(
ConditionalSubscriber<? super T>
actual,
Consumer<? super S>
resourceCleanup,
S
resource,
boolean
eager) {
this.
actual =
actual;
this.
resourceCleanup =
resourceCleanup;
this.
resource =
resource;
this.
eager =
eager;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
TERMINATED ||
key ==
Attr.
CANCELLED)
return
wip == 1;
if (
key ==
Attr.
PARENT) return
s;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
public void
request(long
n) {
s.
request(
n);
}
@
Override
public void
cancel() {
if (
WIP.
compareAndSet(this, 0, 1)) {
s.
cancel();
cleanup();
}
}
void
cleanup() {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
Operators.
onErrorDropped(
e,
actual.
currentContext());
}
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
actual.
onNext(
t);
}
@
Override
public boolean
tryOnNext(T
t) {
return
actual.
tryOnNext(
t);
}
@
Override
public void
onError(
Throwable t) {
if (
eager &&
WIP.
compareAndSet(this, 0, 1)) {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
Throwable _e =
Operators.
onOperatorError(
e,
actual.
currentContext());
t =
Exceptions.
addSuppressed(
_e,
t);
}
}
actual.
onError(
t);
if (!
eager &&
WIP.
compareAndSet(this, 0, 1)) {
cleanup();
}
}
@
Override
public void
onComplete() {
if (
eager &&
WIP.
compareAndSet(this, 0, 1)) {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable e) {
actual.
onError(
Operators.
onOperatorError(
e,
actual.
currentContext()));
return;
}
}
actual.
onComplete();
if (!
eager &&
WIP.
compareAndSet(this, 0, 1)) {
cleanup();
}
}
@
Override
public int
requestFusion(int
requestedMode) {
return
NONE; // always reject, upstream turned out to be non-fuseable after all
}
@
Override
public void
clear() {
// ignoring fusion methods
}
@
Override
public boolean
isEmpty() {
// ignoring fusion methods
return true;
}
@
Override
@
Nullable
public T
poll() {
return null;
}
@
Override
public int
size() {
return 0;
}
}
}