/*
* 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.function.
Consumer;
import java.util.function.
Function;
import reactor.core.
CoreSubscriber;
import reactor.core.
Exceptions;
import reactor.core.
Fuseable;
/**
* 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
MonoUsing<T, S> extends
Mono<T> implements
Fuseable,
SourceProducer<T> {
final
Callable<S>
resourceSupplier;
final
Function<? super S, ? extends
Mono<? extends T>>
sourceFactory;
final
Consumer<? super S>
resourceCleanup;
final boolean
eager;
MonoUsing(
Callable<S>
resourceSupplier,
Function<? super S, ? extends
Mono<? 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;
}
Mono<? extends T>
p;
try {
p =
Objects.
requireNonNull(
sourceFactory.
apply(
resource),
"The sourceFactory returned a null value");
}
catch (
Throwable e) {
try {
resourceCleanup.
accept(
resource);
}
catch (
Throwable ex) {
e =
Exceptions.
addSuppressed(
ex,
Operators.
onOperatorError(
e,
actual.
currentContext()));
}
Operators.
error(
actual,
Operators.
onOperatorError(
e,
actual.
currentContext()));
return;
}
if (
p instanceof
Fuseable) {
p.
subscribe(new
FluxUsing.
UsingFuseableSubscriber<>(
actual,
resourceCleanup,
resource,
eager));
}
else if (
actual instanceof
ConditionalSubscriber) {
p.
subscribe(new
FluxUsing.
UsingConditionalSubscriber<>((
ConditionalSubscriber<? super
T>)
actual,
resourceCleanup,
resource,
eager));
}
else {
p.
subscribe(new
FluxUsing.
UsingSubscriber<>(
actual,
resourceCleanup,
resource,
eager));
}
}
@
Override
public
Object scanUnsafe(
Attr key) {
return null; //no particular key to be represented, still useful in hooks
}
}