/*
* 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.time.
Duration;
import java.util.
Objects;
import java.util.concurrent.
Callable;
import java.util.function.
Supplier;
import reactor.core.
CoreSubscriber;
import reactor.core.
Fuseable;
import reactor.util.annotation.
Nullable;
/**
* Executes a Supplier function and emits a single value to each individual Subscriber.
*
* @param <T> the returned value type
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
MonoSupplier<T>
extends
Mono<T>
implements
Callable<T>,
Fuseable,
SourceProducer<T> {
final
Supplier<? extends T>
supplier;
MonoSupplier(
Supplier<? extends T>
callable) {
this.
supplier =
Objects.
requireNonNull(
callable, "callable");
}
@
Override
public void
subscribe(
CoreSubscriber<? super T>
actual) {
Operators.
MonoSubscriber<T, T>
sds = new
Operators.
MonoSubscriber<>(
actual);
actual.
onSubscribe(
sds);
if (
sds.
isCancelled()) {
return;
}
try {
T
t =
supplier.
get();
if (
t == null) {
sds.
onComplete();
}
else {
sds.
complete(
t);
}
}
catch (
Throwable e) {
actual.
onError(
Operators.
onOperatorError(
e,
actual.
currentContext()));
}
}
@
Override
@
Nullable
public T
block(
Duration m) {
return
supplier.
get();
}
@
Override
@
Nullable
public T
block() {
//the duration is ignored above
return
block(
Duration.
ZERO);
}
@
Override
@
Nullable
public T
call() throws
Exception {
return
supplier.
get();
}
@
Override
public
Object scanUnsafe(
Attr key) {
return null; //no particular key to be represented, still useful in hooks
}
}