/**
* 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.observables;
import java.util.concurrent.
TimeUnit;
import io.reactivex.*;
import io.reactivex.annotations.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.functions.
Consumer;
import io.reactivex.internal.functions.*;
import io.reactivex.internal.operators.observable.*;
import io.reactivex.internal.util.
ConnectConsumer;
import io.reactivex.plugins.
RxJavaPlugins;
import io.reactivex.schedulers.
Schedulers;
/**
* A {@code ConnectableObservable} resembles an ordinary {@link Observable}, except that it does not begin
* emitting items when it is subscribed to, but only when its {@link #connect} method is called. In this way you
* can wait for all intended {@link Observer}s to {@link Observable#subscribe} to the {@code Observable}
* before the {@code Observable} begins emitting items.
* <p>
* <img width="640" height="510" src="https://github.com/ReactiveX/RxJava/wiki/images/rx-operators/publishConnect.png" alt="">
*
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Connectable-Observable-Operators">RxJava Wiki:
* Connectable Observable Operators</a>
* @param <T>
* the type of items emitted by the {@code ConnectableObservable}
*/
public abstract class
ConnectableObservable<T> extends
Observable<T> {
/**
* Instructs the {@code ConnectableObservable} to begin emitting the items from its underlying
* {@link Observable} to its {@link Observer}s.
*
* @param connection
* the action that receives the connection subscription before the subscription to source happens
* allowing the caller to synchronously disconnect a synchronous source
* @see <a href="http://reactivex.io/documentation/operators/connect.html">ReactiveX documentation: Connect</a>
*/
public abstract void
connect(@
NonNull Consumer<? super
Disposable>
connection);
/**
* Instructs the {@code ConnectableObservable} to begin emitting the items from its underlying
* {@link Observable} to its {@link Observer}s.
* <p>
* To disconnect from a synchronous source, use the {@link #connect(Consumer)} method.
*
* @return the subscription representing the connection
* @see <a href="http://reactivex.io/documentation/operators/connect.html">ReactiveX documentation: Connect</a>
*/
public final
Disposable connect() {
ConnectConsumer cc = new
ConnectConsumer();
connect(
cc);
return
cc.
disposable;
}
/**
* Returns an {@code Observable} that stays connected to this {@code ConnectableObservable} as long as there
* is at least one subscription to this {@code ConnectableObservable}.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This {@code refCount} overload does not operate on any particular {@link Scheduler}.</dd>
* </dl>
* @return an {@link Observable}
* @see <a href="http://reactivex.io/documentation/operators/refcount.html">ReactiveX documentation: RefCount</a>
* @see #refCount(int)
* @see #refCount(long, TimeUnit)
* @see #refCount(int, long, TimeUnit)
*/
@
NonNull
@
CheckReturnValue
@
SchedulerSupport(
SchedulerSupport.
NONE)
public
Observable<T>
refCount() {
return
RxJavaPlugins.
onAssembly(new
ObservableRefCount<T>(this));
}
/**
* Connects to the upstream {@code ConnectableObservable} if the number of subscribed
* subscriber reaches the specified count and disconnect if all subscribers have unsubscribed.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This {@code refCount} overload does not operate on any particular {@link Scheduler}.</dd>
* </dl>
* <p>History: 2.1.14 - experimental
* @param subscriberCount the number of subscribers required to connect to the upstream
* @return the new Observable instance
* @since 2.2
*/
@
CheckReturnValue
@
SchedulerSupport(
SchedulerSupport.
NONE)
public final
Observable<T>
refCount(int
subscriberCount) {
return
refCount(
subscriberCount, 0,
TimeUnit.
NANOSECONDS,
Schedulers.
trampoline());
}
/**
* Connects to the upstream {@code ConnectableObservable} if the number of subscribed
* subscriber reaches 1 and disconnect after the specified
* timeout if all subscribers have unsubscribed.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This {@code refCount} overload operates on the {@code computation} {@link Scheduler}.</dd>
* </dl>
* <p>History: 2.1.14 - experimental
* @param timeout the time to wait before disconnecting after all subscribers unsubscribed
* @param unit the time unit of the timeout
* @return the new Observable instance
* @see #refCount(long, TimeUnit, Scheduler)
* @since 2.2
*/
@
CheckReturnValue
@
SchedulerSupport(
SchedulerSupport.
COMPUTATION)
public final
Observable<T>
refCount(long
timeout,
TimeUnit unit) {
return
refCount(1,
timeout,
unit,
Schedulers.
computation());
}
/**
* Connects to the upstream {@code ConnectableObservable} if the number of subscribed
* subscriber reaches 1 and disconnect after the specified
* timeout if all subscribers have unsubscribed.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This {@code refCount} overload operates on the specified {@link Scheduler}.</dd>
* </dl>
* <p>History: 2.1.14 - experimental
* @param timeout the time to wait before disconnecting after all subscribers unsubscribed
* @param unit the time unit of the timeout
* @param scheduler the target scheduler to wait on before disconnecting
* @return the new Observable instance
* @since 2.2
*/
@
CheckReturnValue
@
SchedulerSupport(
SchedulerSupport.
CUSTOM)
public final
Observable<T>
refCount(long
timeout,
TimeUnit unit,
Scheduler scheduler) {
return
refCount(1,
timeout,
unit,
scheduler);
}
/**
* Connects to the upstream {@code ConnectableObservable} if the number of subscribed
* subscriber reaches the specified count and disconnect after the specified
* timeout if all subscribers have unsubscribed.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This {@code refCount} overload operates on the {@code computation} {@link Scheduler}.</dd>
* </dl>
* <p>History: 2.1.14 - experimental
* @param subscriberCount the number of subscribers required to connect to the upstream
* @param timeout the time to wait before disconnecting after all subscribers unsubscribed
* @param unit the time unit of the timeout
* @return the new Observable instance
* @see #refCount(int, long, TimeUnit, Scheduler)
* @since 2.2
*/
@
CheckReturnValue
@
SchedulerSupport(
SchedulerSupport.
COMPUTATION)
public final
Observable<T>
refCount(int
subscriberCount, long
timeout,
TimeUnit unit) {
return
refCount(
subscriberCount,
timeout,
unit,
Schedulers.
computation());
}
/**
* Connects to the upstream {@code ConnectableObservable} if the number of subscribed
* subscriber reaches the specified count and disconnect after the specified
* timeout if all subscribers have unsubscribed.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This {@code refCount} overload operates on the specified {@link Scheduler}.</dd>
* </dl>
* <p>History: 2.1.14 - experimental
* @param subscriberCount the number of subscribers required to connect to the upstream
* @param timeout the time to wait before disconnecting after all subscribers unsubscribed
* @param unit the time unit of the timeout
* @param scheduler the target scheduler to wait on before disconnecting
* @return the new Observable instance
* @since 2.2
*/
@
CheckReturnValue
@
SchedulerSupport(
SchedulerSupport.
CUSTOM)
public final
Observable<T>
refCount(int
subscriberCount, long
timeout,
TimeUnit unit,
Scheduler scheduler) {
ObjectHelper.
verifyPositive(
subscriberCount, "subscriberCount");
ObjectHelper.
requireNonNull(
unit, "unit is null");
ObjectHelper.
requireNonNull(
scheduler, "scheduler is null");
return
RxJavaPlugins.
onAssembly(new
ObservableRefCount<T>(this,
subscriberCount,
timeout,
unit,
scheduler));
}
/**
* Returns an Observable that automatically connects (at most once) to this ConnectableObservable
* when the first Observer subscribes.
* <p>
* <img width="640" height="348" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/autoConnect.o.png" alt="">
* <p>
* The connection happens after the first subscription and happens at most once
* during the lifetime of the returned Observable. If this ConnectableObservable
* terminates, the connection is never renewed, no matter how Observers come
* and go. Use {@link #refCount()} to renew a connection or dispose an active
* connection when all {@code Observers}s have disposed their {@code Disposable}s.
* <p>
* This overload does not allow disconnecting the connection established via
* {@link #connect(Consumer)}. Use the {@link #autoConnect(int, Consumer)} overload
* to gain access to the {@code Disposable} representing the only connection.
*
* @return an Observable that automatically connects to this ConnectableObservable
* when the first Observer subscribes
*/
@
NonNull
public
Observable<T>
autoConnect() {
return
autoConnect(1);
}
/**
* Returns an Observable that automatically connects (at most once) to this ConnectableObservable
* when the specified number of Observers subscribe to it.
* <p>
* <img width="640" height="348" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/autoConnect.o.png" alt="">
* <p>
* The connection happens after the given number of subscriptions and happens at most once
* during the lifetime of the returned Observable. If this ConnectableObservable
* terminates, the connection is never renewed, no matter how Observers come
* and go. Use {@link #refCount()} to renew a connection or dispose an active
* connection when all {@code Observers}s have disposed their {@code Disposable}s.
* <p>
* This overload does not allow disconnecting the connection established via
* {@link #connect(Consumer)}. Use the {@link #autoConnect(int, Consumer)} overload
* to gain access to the {@code Disposable} representing the only connection.
*
* @param numberOfSubscribers the number of subscribers to await before calling connect
* on the ConnectableObservable. A non-positive value indicates
* an immediate connection.
* @return an Observable that automatically connects to this ConnectableObservable
* when the specified number of Subscribers subscribe to it
*/
@
NonNull
public
Observable<T>
autoConnect(int
numberOfSubscribers) {
return
autoConnect(
numberOfSubscribers,
Functions.
emptyConsumer());
}
/**
* Returns an Observable that automatically connects (at most once) to this ConnectableObservable
* when the specified number of Subscribers subscribe to it and calls the
* specified callback with the Subscription associated with the established connection.
* <p>
* <img width="640" height="348" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/autoConnect.o.png" alt="">
* <p>
* The connection happens after the given number of subscriptions and happens at most once
* during the lifetime of the returned Observable. If this ConnectableObservable
* terminates, the connection is never renewed, no matter how Observers come
* and go. Use {@link #refCount()} to renew a connection or dispose an active
* connection when all {@code Observers}s have disposed their {@code Disposable}s.
*
* @param numberOfSubscribers the number of subscribers to await before calling connect
* on the ConnectableObservable. A non-positive value indicates
* an immediate connection.
* @param connection the callback Consumer that will receive the Subscription representing the
* established connection
* @return an Observable that automatically connects to this ConnectableObservable
* when the specified number of Subscribers subscribe to it and calls the
* specified callback with the Subscription associated with the established connection
*/
@
NonNull
public
Observable<T>
autoConnect(int
numberOfSubscribers, @
NonNull Consumer<? super
Disposable>
connection) {
if (
numberOfSubscribers <= 0) {
this.
connect(
connection);
return
RxJavaPlugins.
onAssembly(this);
}
return
RxJavaPlugins.
onAssembly(new
ObservableAutoConnect<T>(this,
numberOfSubscribers,
connection));
}
}