/*
 * 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 java.util.Objects;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.function.Consumer;

import reactor.core.CoreSubscriber;
import reactor.core.Disposable;
import reactor.core.Scannable;
import reactor.util.annotation.Nullable;

Connects to the underlying Flux once the given amount of Subscribers subscribed.
Type parameters:
  • <T> – the value type
See Also:
/** * Connects to the underlying Flux once the given amount of Subscribers * subscribed. * * @param <T> the value type * @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a> */
final class FluxAutoConnect<T> extends Flux<T> implements Scannable { final ConnectableFlux<? extends T> source; final Consumer<? super Disposable> cancelSupport; volatile int remaining; @SuppressWarnings("rawtypes") static final AtomicIntegerFieldUpdater<FluxAutoConnect> REMAINING = AtomicIntegerFieldUpdater.newUpdater(FluxAutoConnect.class, "remaining"); FluxAutoConnect(ConnectableFlux<? extends T> source, int n, Consumer<? super Disposable> cancelSupport) { if (n <= 0) { throw new IllegalArgumentException("n > required but it was " + n); } this.source = Objects.requireNonNull(source, "source"); this.cancelSupport = Objects.requireNonNull(cancelSupport, "cancelSupport"); REMAINING.lazySet(this, n); } @Override public void subscribe(CoreSubscriber<? super T> actual) { source.subscribe(actual); if (remaining > 0 && REMAINING.decrementAndGet(this) == 0) { source.connect(cancelSupport); } } @Override public int getPrefetch() { return source.getPrefetch(); } @Override @Nullable public Object scanUnsafe(Attr key) { if (key == Attr.PREFETCH) return getPrefetch(); if (key == Attr.PARENT) return source; if (key == Attr.CAPACITY) return remaining; if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return null; } }