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Reactive Extensions for Java
/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* 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 io.reactivex.internal.operators.flowable;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.flowables.ConnectableFlowable;
import io.reactivex.functions.Consumer;
import io.reactivex.internal.disposables.*;
import io.reactivex.internal.subscriptions.SubscriptionHelper;
import io.reactivex.plugins.RxJavaPlugins;
/**
* Returns an observable sequence that stays connected to the source as long as
* there is at least one subscription to the observable sequence.
*
* @param
* the value type
*/
public final class FlowableRefCount extends Flowable {
final ConnectableFlowable source;
final int n;
final long timeout;
final TimeUnit unit;
final Scheduler scheduler;
RefConnection connection;
public FlowableRefCount(ConnectableFlowable source) {
this(source, 1, 0L, TimeUnit.NANOSECONDS, null);
}
public FlowableRefCount(ConnectableFlowable source, int n, long timeout, TimeUnit unit,
Scheduler scheduler) {
this.source = source;
this.n = n;
this.timeout = timeout;
this.unit = unit;
this.scheduler = scheduler;
}
@Override
protected void subscribeActual(Subscriber s) {
RefConnection conn;
boolean connect = false;
synchronized (this) {
conn = connection;
if (conn == null) {
conn = new RefConnection(this);
connection = conn;
}
long c = conn.subscriberCount;
if (c == 0L && conn.timer != null) {
conn.timer.dispose();
}
conn.subscriberCount = c + 1;
if (!conn.connected && c + 1 == n) {
connect = true;
conn.connected = true;
}
}
source.subscribe(new RefCountSubscriber(s, this, conn));
if (connect) {
source.connect(conn);
}
}
void cancel(RefConnection rc) {
SequentialDisposable sd;
synchronized (this) {
if (connection == null || connection != rc) {
return;
}
long c = rc.subscriberCount - 1;
rc.subscriberCount = c;
if (c != 0L || !rc.connected) {
return;
}
if (timeout == 0L) {
timeout(rc);
return;
}
sd = new SequentialDisposable();
rc.timer = sd;
}
sd.replace(scheduler.scheduleDirect(rc, timeout, unit));
}
void terminated(RefConnection rc) {
synchronized (this) {
if (source instanceof FlowablePublishClassic) {
if (connection != null && connection == rc) {
connection = null;
clearTimer(rc);
}
if (--rc.subscriberCount == 0) {
reset(rc);
}
} else {
if (connection != null && connection == rc) {
clearTimer(rc);
if (--rc.subscriberCount == 0) {
connection = null;
reset(rc);
}
}
}
}
}
void clearTimer(RefConnection rc) {
if (rc.timer != null) {
rc.timer.dispose();
rc.timer = null;
}
}
void reset(RefConnection rc) {
if (source instanceof Disposable) {
((Disposable)source).dispose();
} else if (source instanceof ResettableConnectable) {
((ResettableConnectable)source).resetIf(rc.get());
}
}
void timeout(RefConnection rc) {
synchronized (this) {
if (rc.subscriberCount == 0 && rc == connection) {
connection = null;
Disposable connectionObject = rc.get();
DisposableHelper.dispose(rc);
if (source instanceof Disposable) {
((Disposable)source).dispose();
} else if (source instanceof ResettableConnectable) {
if (connectionObject == null) {
rc.disconnectedEarly = true;
} else {
((ResettableConnectable)source).resetIf(connectionObject);
}
}
}
}
}
static final class RefConnection extends AtomicReference
implements Runnable, Consumer {
private static final long serialVersionUID = -4552101107598366241L;
final FlowableRefCount parent;
Disposable timer;
long subscriberCount;
boolean connected;
boolean disconnectedEarly;
RefConnection(FlowableRefCount parent) {
this.parent = parent;
}
@Override
public void run() {
parent.timeout(this);
}
@Override
public void accept(Disposable t) throws Exception {
DisposableHelper.replace(this, t);
synchronized (parent) {
if (disconnectedEarly) {
((ResettableConnectable)parent.source).resetIf(t);
}
}
}
}
static final class RefCountSubscriber
extends AtomicBoolean implements FlowableSubscriber, Subscription {
private static final long serialVersionUID = -7419642935409022375L;
final Subscriber downstream;
final FlowableRefCount parent;
final RefConnection connection;
Subscription upstream;
RefCountSubscriber(Subscriber actual, FlowableRefCount parent, RefConnection connection) {
this.downstream = actual;
this.parent = parent;
this.connection = connection;
}
@Override
public void onNext(T t) {
downstream.onNext(t);
}
@Override
public void onError(Throwable t) {
if (compareAndSet(false, true)) {
parent.terminated(connection);
downstream.onError(t);
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public void onComplete() {
if (compareAndSet(false, true)) {
parent.terminated(connection);
downstream.onComplete();
}
}
@Override
public void request(long n) {
upstream.request(n);
}
@Override
public void cancel() {
upstream.cancel();
if (compareAndSet(false, true)) {
parent.cancel(connection);
}
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(upstream, s)) {
this.upstream = s;
downstream.onSubscribe(this);
}
}
}
}