/*
* 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.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.
*
* @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;
return null;
}
}