/**
* 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 io.reactivex.annotations.NonNull;
import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.functions.Consumer;
import io.reactivex.internal.functions.Functions;
import io.reactivex.internal.operators.observable.*;
import io.reactivex.internal.util.ConnectConsumer;
import io.reactivex.plugins.RxJavaPlugins;
/**
* 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}.
*
* @return an {@link Observable}
* @see <a href="http://reactivex.io/documentation/operators/refcount.html">ReactiveX documentation: RefCount</a>
*/
@NonNull
public Observable<T> refCount() {
return RxJavaPlugins.onAssembly(new ObservableRefCount<T>(this));
}
/**
* Returns an Observable that automatically connects to this ConnectableObservable
* when the first Observer subscribes.
*
* @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 to this ConnectableObservable
* when the specified number of Observers subscribe to it.
*
* @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 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.
*
* @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));
}
}