/*
 * 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
 *
 *       https://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 reactor.core.CoreSubscriber;
import reactor.core.Fuseable;
import reactor.util.annotation.Nullable;

Represents an empty publisher which only calls onSubscribe and onComplete.

This Publisher is effectively stateless and only a single instance exists. Use the instance() method to obtain a properly type-parametrized view of it.

See Also:
/** * Represents an empty publisher which only calls onSubscribe and onComplete. * <p> * This Publisher is effectively stateless and only a single instance exists. * Use the {@link #instance()} method to obtain a properly type-parametrized view of it. * @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a> */
final class FluxEmpty extends Flux<Object> implements Fuseable.ScalarCallable<Object>, SourceProducer<Object> { private static final Flux<Object> INSTANCE = new FluxEmpty(); private FluxEmpty() { // deliberately no op } @Override public void subscribe(CoreSubscriber<? super Object> actual) { Operators.complete(actual); } @Override public Object scanUnsafe(Attr key) { if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return null; }
Returns a properly parametrized instance of this empty Publisher.
Type parameters:
  • <T> – the output type
Returns:a properly parametrized instance of this empty Publisher
/** * Returns a properly parametrized instance of this empty Publisher. * * @param <T> the output type * @return a properly parametrized instance of this empty Publisher */
@SuppressWarnings("unchecked") public static <T> Flux<T> instance() { return (Flux<T>) INSTANCE; } @Override @Nullable public Object call() throws Exception { return null; /* Scalar optimizations on empty */ } }