src/main/java/rx/Single.java
/**
* Copyright 2015 Netflix, Inc.
*
* 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 rx;
import java.util.Collection;
import java.util.concurrent.*;
import rx.Observable.Operator;
import rx.annotations.*;
import rx.exceptions.*;
import rx.functions.*;
import rx.internal.observers.AssertableSubscriberObservable;
import rx.internal.operators.*;
import rx.internal.util.*;
import rx.observables.ConnectableObservable;
import rx.observers.*;
import rx.plugins.RxJavaHooks;
import rx.schedulers.Schedulers;
import rx.singles.BlockingSingle;
import rx.subscriptions.Subscriptions;
/**
* The Single class implements the Reactive Pattern for a single value response. See {@link Observable} for the
* implementation of the Reactive Pattern for a stream or vector of values.
* <p>
* {@code Single} behaves the same as {@link Observable} except that it can only emit either a single successful
* value, or an error (there is no "onComplete" notification as there is for {@link Observable})
* <p>
* Like an {@link Observable}, a {@code Single} is lazy, can be either "hot" or "cold", synchronous or
* asynchronous.
* <p>
* The documentation for this class makes use of marble diagrams. The following legend explains these diagrams:
* <p>
* <img width="605" height="285" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.legend.png" alt="">
* <p>
* For more information see the <a href="http://reactivex.io/documentation/observable.html">ReactiveX
* documentation</a>.
*
* @param <T>
* the type of the item emitted by the Single
* @since 1.2
*/
public class Single<T> {
final OnSubscribe<T> onSubscribe;
/**
* Creates a Single with a Function to execute when it is subscribed to (executed).
* <p>
* <em>Note:</em> Use {@link #create(OnSubscribe)} to create a Single, instead of this constructor,
* unless you specifically have a need for inheritance.
*
* @param f
* {@code f} to be executed when {@code execute(SingleSubscriber)} or
* {@code subscribe(Subscriber)} is called
*/
protected Single(OnSubscribe<T> f) {
this.onSubscribe = RxJavaHooks.onCreate(f);
}
/**
* Creates a Single with a Function to execute when it is subscribed to (executed).
* <p>
* <em>Note:</em> Use {@link #create(OnSubscribe)} to create a Single, instead of this constructor,
* unless you specifically have a need for inheritance.
*
* @param f
* {@code f} to be executed when {@code execute(SingleSubscriber)} or
* {@code subscribe(Subscriber)} is called
* @deprecated 1.2.1: Not recommended, use {@link #Single(OnSubscribe)} to avoid wrapping and
* conversion between the Observable and Single protocols.
*/
@Deprecated
protected Single(final Observable.OnSubscribe<T> f) {
onSubscribe = RxJavaHooks.onCreate(new SingleFromObservable<T>(f));
}
/**
* Returns a Single that will execute the specified function when a {@link SingleSubscriber} executes it or
* a {@link Subscriber} subscribes to it.
* <p>
* <img width="640" height="200" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.create.png" alt="">
* <p>
* Write the function you pass to {@code create} so that it behaves as a Single: It should invoke the
* SingleSubscriber {@link SingleSubscriber#onSuccess onSuccess} and/or
* {@link SingleSubscriber#onError onError} methods appropriately.
* <p>
* A well-formed Single must invoke either the SingleSubscriber's {@code onSuccess} method exactly once or
* its {@code onError} method exactly once.
* <p>
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code create} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T>
* the type of the item that this Single emits
* @param f
* a function that accepts an {@code SingleSubscriber<T>}, and invokes its {@code onSuccess} or
* {@code onError} methods as appropriate
* @return a Single that, when a {@link Subscriber} subscribes to it, will execute the specified function
* @see <a href="http://reactivex.io/documentation/operators/create.html">ReactiveX operators documentation: Create</a>
*/
public static <T> Single<T> create(OnSubscribe<T> f) {
return new Single<T>(f);
}
/**
* Invoked when Single.execute is called.
* @param <T> the output value type
*/
public interface OnSubscribe<T> extends Action1<SingleSubscriber<? super T>> {
// cover for generics insanity
}
/**
* Lifts a function to the current Single and returns a new Single that when subscribed to will pass the
* values of the current Single through the Operator function.
* <p>
* In other words, this allows chaining TaskExecutors together on a Single for acting on the values within
* the Single.
* <p>
* {@code task.map(...).filter(...).lift(new OperatorA()).lift(new OperatorB(...)).subscribe() }
* <p>
* If the operator you are creating is designed to act on the item emitted by a source Single, use
* {@code lift}. If your operator is designed to transform the source Single as a whole (for instance, by
* applying a particular set of existing RxJava operators to it) use {@link #compose}.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code lift} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <R> the downstream's value type (output)
* @param lift
* the Operator that implements the Single-operating function to be applied to the source Single
* @return a Single that is the result of applying the lifted Operator to the source Single
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Implementing-Your-Own-Operators">RxJava wiki: Implementing Your Own Operators</a>
* @since 1.3
*/
public final <R> Single<R> lift(final Operator<? extends R, ? super T> lift) {
return create(new SingleLiftObservableOperator<T, R>(this.onSubscribe, lift));
}
/**
* Transform a Single by applying a particular Transformer function to it.
* <p>
* This method operates on the Single itself whereas {@link #lift} operates on the Single's Subscribers or
* Observers.
* <p>
* If the operator you are creating is designed to act on the individual item emitted by a Single, use
* {@link #lift}. If your operator is designed to transform the source Single as a whole (for instance, by
* applying a particular set of existing RxJava operators to it) use {@code compose}.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code compose} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <R> the value type of the single returned by the transformer function
* @param transformer
* implements the function that transforms the source Single
* @return the source Single, transformed by the transformer function
* @see <a href="https://github.com/ReactiveX/RxJava/wiki/Implementing-Your-Own-Operators">RxJava wiki: Implementing Your Own Operators</a>
*/
@SuppressWarnings("unchecked")
public <R> Single<R> compose(Transformer<? super T, ? extends R> transformer) {
return ((Transformer<T, R>) transformer).call(this);
}
/**
* Convenience type that allows a function to fluently transform a
* Single into another Single via {@link #compose}.
* <pre>
* Transformer<Integer, Integer> transformer = s ->
* s.subscribeOn(Schedulers.io())
* .observeOn(AndroidSchedulers.mainThread());
*
* Single.just(1)
* .compose(transformer)
* .subscribe(System.out::println);
* </pre>
*
* @param <T> the source Single's value type
* @param <R> the transformed Single's value type
*/
public interface Transformer<T, R> extends Func1<Single<T>, Single<R>> {
// cover for generics insanity
}
/**
* Hides the identity of this Single.
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.toObservable.png" alt="">
*/
private static <T> Observable<T> asObservable(Single<T> t) {
// is this sufficient, or do I need to keep the outer Single and subscribe to it?
return Observable.unsafeCreate(new SingleToObservable<T>(t.onSubscribe));
}
/* *********************************************************************************************************
* Operators Below Here
* *********************************************************************************************************
*/
/**
* Casts the success value of the current Single into the target type or signals a
* ClassCastException if not compatible.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code cast} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
* @param <R> the target type
* @param klass the type token to use for casting the success result from the current Single
* @return the new Single instance
* @since 1.3.1 - experimental
*/
@Experimental
public final <R> Single<R> cast(final Class<R> klass) {
return map(new SingleOperatorCast<T, R>(klass));
}
/**
* Returns an Observable that emits the items emitted by two Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @return an Observable that emits items emitted by the two source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2) {
return Observable.concat(asObservable(t1), asObservable(t2));
}
/**
* Returns an Observable that emits the items emitted by three Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @param t3
* a Single to be concatenated
* @return an Observable that emits items emitted by the three source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3) {
return Observable.concat(asObservable(t1), asObservable(t2), asObservable(t3));
}
/**
* Returns an Observable that emits the items emitted by four Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @param t3
* a Single to be concatenated
* @param t4
* a Single to be concatenated
* @return an Observable that emits items emitted by the four source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4) {
return Observable.concat(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4));
}
/**
* Returns an Observable that emits the items emitted by five Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @param t3
* a Single to be concatenated
* @param t4
* a Single to be concatenated
* @param t5
* a Single to be concatenated
* @return an Observable that emits items emitted by the five source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5) {
return Observable.concat(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5));
}
/**
* Returns an Observable that emits the items emitted by six Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @param t3
* a Single to be concatenated
* @param t4
* a Single to be concatenated
* @param t5
* a Single to be concatenated
* @param t6
* a Single to be concatenated
* @return an Observable that emits items emitted by the six source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6) {
return Observable.concat(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6));
}
/**
* Returns an Observable that emits the items emitted by seven Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @param t3
* a Single to be concatenated
* @param t4
* a Single to be concatenated
* @param t5
* a Single to be concatenated
* @param t6
* a Single to be concatenated
* @param t7
* a Single to be concatenated
* @return an Observable that emits items emitted by the seven source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6, Single<? extends T> t7) {
return Observable.concat(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6), asObservable(t7));
}
/**
* Returns an Observable that emits the items emitted by eight Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @param t3
* a Single to be concatenated
* @param t4
* a Single to be concatenated
* @param t5
* a Single to be concatenated
* @param t6
* a Single to be concatenated
* @param t7
* a Single to be concatenated
* @param t8
* a Single to be concatenated
* @return an Observable that emits items emitted by the eight source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6, Single<? extends T> t7, Single<? extends T> t8) {
return Observable.concat(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6), asObservable(t7), asObservable(t8));
}
/**
* Returns an Observable that emits the items emitted by nine Singles, one after the other.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concat.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be concatenated
* @param t2
* a Single to be concatenated
* @param t3
* a Single to be concatenated
* @param t4
* a Single to be concatenated
* @param t5
* a Single to be concatenated
* @param t6
* a Single to be concatenated
* @param t7
* a Single to be concatenated
* @param t8
* a Single to be concatenated
* @param t9
* a Single to be concatenated
* @return an Observable that emits items emitted by the nine source Singles, one after the other.
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public static <T> Observable<T> concat(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6, Single<? extends T> t7, Single<? extends T> t8, Single<? extends T> t9) {
return Observable.concat(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6), asObservable(t7), asObservable(t8), asObservable(t9));
}
/**
* Returns a Single that invokes a subscriber's {@link SingleSubscriber#onError onError} method when the
* subscriber subscribes to it.
* <p>
* <img width="640" height="190" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.error.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code error} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param exception
* the particular Throwable to pass to {@link SingleSubscriber#onError onError}
* @param <T>
* the type of the item (ostensibly) emitted by the Single
* @return a Single that invokes the subscriber's {@link SingleSubscriber#onError onError} method when
* the subscriber subscribes to it
* @see <a href="http://reactivex.io/documentation/operators/empty-never-throw.html">ReactiveX operators documentation: Throw</a>
*/
public static <T> Single<T> error(final Throwable exception) {
return Single.create(new OnSubscribe<T>() {
@Override
public void call(SingleSubscriber<? super T> te) {
te.onError(exception);
}
});
}
/**
* Converts a {@link Future} into a {@code Single}.
* <p>
* <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.from.Future.png" alt="">
* <p>
* You can convert any object that supports the {@link Future} interface into a Single that emits the return
* value of the {@link Future#get} method of that object, by passing the object into the {@code from}
* method.
* <p>
* <em>Important note:</em> This Single is blocking; you cannot unsubscribe from it.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code from} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param future
* the source {@link Future}
* @param <T>
* the type of object that the {@link Future} returns, and also the type of item to be emitted by
* the resulting {@code Single}
* @return a {@code Single} that emits the item from the source {@link Future}
* @see <a href="http://reactivex.io/documentation/operators/from.html">ReactiveX operators documentation: From</a>
*/
public static <T> Single<T> from(Future<? extends T> future) {
return create(new SingleFromFuture<T>(future, 0, null));
}
/**
* Converts a {@link Future} into a {@code Single}, with a timeout on the Future.
* <p>
* <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.from.Future.png" alt="">
* <p>
* You can convert any object that supports the {@link Future} interface into a {@code Single} that emits
* the return value of the {@link Future#get} method of that object, by passing the object into the
* {@code from} method.
* <p>
* <em>Important note:</em> This {@code Single} is blocking; you cannot unsubscribe from it.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code from} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param future
* the source {@link Future}
* @param timeout
* the maximum time to wait before calling {@code get}
* @param unit
* the {@link TimeUnit} of the {@code timeout} argument
* @param <T>
* the type of object that the {@link Future} returns, and also the type of item to be emitted by
* the resulting {@code Single}
* @return a {@code Single} that emits the item from the source {@link Future}
* @see <a href="http://reactivex.io/documentation/operators/from.html">ReactiveX operators documentation: From</a>
*/
public static <T> Single<T> from(Future<? extends T> future, long timeout, TimeUnit unit) {
if (unit == null) {
throw new NullPointerException("unit is null");
}
return create(new SingleFromFuture<T>(future, timeout, unit));
}
/**
* Converts a {@link Future}, operating on a specified {@link Scheduler}, into a {@code Single}.
* <p>
* <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.from.Future.s.png" alt="">
* <p>
* You can convert any object that supports the {@link Future} interface into a {@code Single} that emits
* the return value of the {@link Future#get} method of that object, by passing the object into the
* {@code from} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>you specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param future
* the source {@link Future}
* @param scheduler
* the {@link Scheduler} to wait for the Future on. Use a Scheduler such as
* {@link Schedulers#io()} that can block and wait on the Future
* @param <T>
* the type of object that the {@link Future} returns, and also the type of item to be emitted by
* the resulting {@code Single}
* @return a {@code Single} that emits the item from the source {@link Future}
* @see <a href="http://reactivex.io/documentation/operators/from.html">ReactiveX operators documentation: From</a>
*/
public static <T> Single<T> from(Future<? extends T> future, Scheduler scheduler) {
return from(future).subscribeOn(scheduler);
}
/**
* Returns a {@link Single} that invokes passed function and emits its result for each new Observer that subscribes.
* <p>
* Allows you to defer execution of passed function until Observer subscribes to the {@link Single}.
* It makes passed function "lazy".
* Result of the function invocation will be emitted by the {@link Single}.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code fromCallable} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param func
* function which execution should be deferred, it will be invoked when Observer will subscribe to the {@link Single}.
* @param <T>
* the type of the item emitted by the {@link Single}.
* @return a {@link Single} whose {@link Observer}s' subscriptions trigger an invocation of the given function.
*/
public static <T> Single<T> fromCallable(final Callable<? extends T> func) {
return create(new SingleFromCallable<T>(func));
}
/**
* Provides an API (in a cold Single) that bridges the Single-reactive world
* with the callback-based world.
* <p>The {@link SingleEmitter} allows registering a callback for
* cancellation/unsubscription of a resource.
* <p>
* Example:
* <pre><code>
* Single.fromEmitter(emitter -> {
* Callback listener = new Callback() {
* @Override
* public void onEvent(Event e) {
* emitter.onSuccess(e.getData());
* }
*
* @Override
* public void onFailure(Exception e) {
* emitter.onError(e);
* }
* };
*
* AutoCloseable c = api.someMethod(listener);
*
* emitter.setCancellation(c::close);
*
* });
* </code></pre>
* <p>All of the SingleEmitter's methods are thread-safe and ensure the
* Single's protocol are held.
* <p>History: 1.2.3 - experimental
* @param <T> the success value type
* @param producer the callback invoked for each incoming SingleSubscriber
* @return the new Single instance
* @since 1.3
*/
public static <T> Single<T> fromEmitter(Action1<SingleEmitter<T>> producer) {
if (producer == null) { throw new NullPointerException("producer is null"); }
return create(new SingleFromEmitter<T>(producer));
}
/**
* Returns a {@code Single} that emits a specified item.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.just.png" alt="">
* <p>
* To convert any object into a {@code Single} that emits that object, pass that object into the
* {@code just} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code just} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param value
* the item to emit
* @param <T>
* the type of that item
* @return a {@code Single} that emits {@code value}
* @see <a href="http://reactivex.io/documentation/operators/just.html">ReactiveX operators documentation: Just</a>
*/
public static <T> Single<T> just(final T value) {
return ScalarSynchronousSingle.create(value);
}
/**
* Flattens a {@code Single} that emits a {@code Single} into a single {@code Single} that emits the item
* emitted by the nested {@code Single}, without any transformation.
* <p>
* <img width="640" height="370" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.oo.png" alt="">
* <p>
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the value type of the sources and the output
* @param source
* a {@code Single} that emits a {@code Single}
* @return a {@code Single} that emits the item that is the result of flattening the {@code Single} emitted
* by {@code source}
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static <T> Single<T> merge(final Single<? extends Single<? extends T>> source) {
if (source instanceof ScalarSynchronousSingle) {
return ((ScalarSynchronousSingle<T>) source).scalarFlatMap((Func1) UtilityFunctions.identity());
}
return Single.create(new OnSubscribe<T>() {
@Override
public void call(final SingleSubscriber<? super T> child) {
SingleSubscriber<Single<? extends T>> parent = new SingleSubscriber<Single<? extends T>>() {
@Override
public void onSuccess(Single<? extends T> innerSingle) {
innerSingle.subscribe(child);
}
@Override
public void onError(Throwable error) {
child.onError(error);
}
};
child.add(parent);
source.subscribe(parent);
}
});
}
/**
* Flattens two Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by
* using the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2) {
return Observable.merge(asObservable(t1), asObservable(t2));
}
/**
* Flattens three Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @param t3
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3) {
return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3));
}
/**
* Flattens four Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @param t3
* a Single to be merged
* @param t4
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4) {
return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4));
}
/**
* Flattens five Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @param t3
* a Single to be merged
* @param t4
* a Single to be merged
* @param t5
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5) {
return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5));
}
/**
* Flattens six Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @param t3
* a Single to be merged
* @param t4
* a Single to be merged
* @param t5
* a Single to be merged
* @param t6
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6) {
return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6));
}
/**
* Flattens seven Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @param t3
* a Single to be merged
* @param t4
* a Single to be merged
* @param t5
* a Single to be merged
* @param t6
* a Single to be merged
* @param t7
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6, Single<? extends T> t7) {
return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6), asObservable(t7));
}
/**
* Flattens eight Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @param t3
* a Single to be merged
* @param t4
* a Single to be merged
* @param t5
* a Single to be merged
* @param t6
* a Single to be merged
* @param t7
* a Single to be merged
* @param t8
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6, Single<? extends T> t7, Single<? extends T> t8) {
return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6), asObservable(t7), asObservable(t8));
}
/**
* Flattens nine Singles into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code merge} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the common value type
* @param t1
* a Single to be merged
* @param t2
* a Single to be merged
* @param t3
* a Single to be merged
* @param t4
* a Single to be merged
* @param t5
* a Single to be merged
* @param t6
* a Single to be merged
* @param t7
* a Single to be merged
* @param t8
* a Single to be merged
* @param t9
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6, Single<? extends T> t7, Single<? extends T> t8, Single<? extends T> t9) {
return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6), asObservable(t7), asObservable(t8), asObservable(t9));
}
/**
* Merges all Singles emitted by the Observable and runs them together until the source
* Observable and all inner Singles complete normally.
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>The operator consumes items from the Observable in an unbounded manner and honors downstream backpressure.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
* <p>History: 1.2.7 - experimental
* @param <T> the value type of the inner Singles and the resulting Observable
* @param sources the Observable that emits Singles to be merged
* @return the new Observable instance
* @see #merge(Observable, int)
* @see #mergeDelayError(Observable)
* @see #mergeDelayError(Observable, int)
* @since 1.3
*/
public static <T> Observable<T> merge(Observable<? extends Single<? extends T>> sources) {
return merge(sources, Integer.MAX_VALUE);
}
/**
* Merges the Singles emitted by the Observable and runs up to the given number of them together at a time,
* until the Observable and all inner Singles terminate.
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>The operator consumes at most maxConcurrent items from the Observable and one-by-one after as the inner
* Singles terminate. The operator ignores downstream backpressure as it doesn't emit items but
* only the terminal event.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code flatMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
* <p>History: 1.2.7 - experimental
* @param <T> the value type of the inner Singles and the resulting Observable
* @param sources the Observable that emits Singles to be merged
* @param maxConcurrency the maximum number of inner Singles to run at a time
* @return the new Observable instance
* @since 1.3
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static <T> Observable<T> merge(Observable<? extends Single<? extends T>> sources, int maxConcurrency) {
return sources.flatMapSingle((Func1)UtilityFunctions.identity(), false, maxConcurrency);
}
/**
* Merges all Singles emitted by the Observable and runs them together,
* delaying errors from them and the Observable, until the source
* Observable and all inner Singles complete normally.
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>The operator consumes items from the Observable in an unbounded manner and honors downstream backpressure.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code merge} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
* <p>History: 1.2.7 - experimental
* @param <T> the value type of the inner Singles and the resulting Observable
* @param sources the Observable that emits Singles to be merged
* @return the new Observable instance
* @see #mergeDelayError(Observable, int)
* @see #merge(Observable)
* @see #merge(Observable, int)
* @since 1.3
*/
public static <T> Observable<T> mergeDelayError(Observable<? extends Single<? extends T>> sources) {
return merge(sources, Integer.MAX_VALUE);
}
/**
* Merges the Singles emitted by the Observable and runs up to the given number of them together at a time,
* delaying errors from them and the Observable, until the Observable and all inner Singles terminate.
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>The operator consumes at most maxConcurrent items from the Observable and one-by-one after as the inner
* Singles terminate. The operator ignores downstream backpressure as it doesn't emit items but
* only the terminal event.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code flatMapSingle} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
* <p>History: 1.2.7 - experimental
* @param <T> the value type of the inner Singles and the resulting Observable
* @param sources the Observable that emits Singles to be merged
* @param maxConcurrency the maximum number of inner Singles to run at a time
* @return the new Observable instance
* @since 1.3
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static <T> Observable<T> mergeDelayError(Observable<? extends Single<? extends T>> sources, int maxConcurrency) {
return sources.flatMapSingle((Func1)UtilityFunctions.identity(), true, maxConcurrency);
}
/**
* Returns a Single that emits the results of a specified combiner function applied to two items emitted by
* two other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, final Func2<? super T1, ? super T2, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1]);
}
});
}
/**
* Returns a Single that emits the results of a specified combiner function applied to three items emitted
* by three other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <T3> the third source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param s3
* a third source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, T3, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, Single<? extends T3> s3, final Func3<? super T1, ? super T2, ? super T3, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2, s3}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1], (T3) args[2]);
}
});
}
/**
* Returns an Observable that emits the results of a specified combiner function applied to four items
* emitted by four other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <T3> the third source Single's value type
* @param <T4> the fourth source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param s3
* a third source Single
* @param s4
* a fourth source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, T3, T4, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, Single<? extends T3> s3, Single<? extends T4> s4, final Func4<? super T1, ? super T2, ? super T3, ? super T4, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2, s3, s4}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1], (T3) args[2], (T4) args[3]);
}
});
}
/**
* Returns an Observable that emits the results of a specified combiner function applied to five items
* emitted by five other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <T3> the third source Single's value type
* @param <T4> the fourth source Single's value type
* @param <T5> the fifth source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param s3
* a third source Single
* @param s4
* a fourth source Single
* @param s5
* a fifth source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, T3, T4, T5, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, Single<? extends T3> s3, Single<? extends T4> s4, Single<? extends T5> s5, final Func5<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2, s3, s4, s5}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1], (T3) args[2], (T4) args[3], (T5) args[4]);
}
});
}
/**
* Returns an Observable that emits the results of a specified combiner function applied to six items
* emitted by six other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <T3> the third source Single's value type
* @param <T4> the fourth source Single's value type
* @param <T5> the fifth source Single's value type
* @param <T6> the sixth source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param s3
* a third source Single
* @param s4
* a fourth source Single
* @param s5
* a fifth source Single
* @param s6
* a sixth source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, T3, T4, T5, T6, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, Single<? extends T3> s3, Single<? extends T4> s4, Single<? extends T5> s5, Single<? extends T6> s6,
final Func6<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, ? super T6, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2, s3, s4, s5, s6}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1], (T3) args[2], (T4) args[3], (T5) args[4], (T6) args[5]);
}
});
}
/**
* Returns an Observable that emits the results of a specified combiner function applied to seven items
* emitted by seven other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <T3> the third source Single's value type
* @param <T4> the fourth source Single's value type
* @param <T5> the fifth source Single's value type
* @param <T6> the sixth source Single's value type
* @param <T7> the seventh source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param s3
* a third source Single
* @param s4
* a fourth source Single
* @param s5
* a fifth source Single
* @param s6
* a sixth source Single
* @param s7
* a seventh source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, T3, T4, T5, T6, T7, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, Single<? extends T3> s3, Single<? extends T4> s4, Single<? extends T5> s5, Single<? extends T6> s6, Single<? extends T7> s7,
final Func7<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, ? super T6, ? super T7, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2, s3, s4, s5, s6, s7}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1], (T3) args[2], (T4) args[3], (T5) args[4], (T6) args[5], (T7) args[6]);
}
});
}
/**
* Returns an Observable that emits the results of a specified combiner function applied to eight items
* emitted by eight other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <T3> the third source Single's value type
* @param <T4> the fourth source Single's value type
* @param <T5> the fifth source Single's value type
* @param <T6> the sixth source Single's value type
* @param <T7> the seventh source Single's value type
* @param <T8> the eighth source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param s3
* a third source Single
* @param s4
* a fourth source Single
* @param s5
* a fifth source Single
* @param s6
* a sixth source Single
* @param s7
* a seventh source Single
* @param s8
* an eighth source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, T3, T4, T5, T6, T7, T8, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, Single<? extends T3> s3, Single<? extends T4> s4, Single<? extends T5> s5, Single<? extends T6> s6, Single<? extends T7> s7, Single<? extends T8> s8,
final Func8<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, ? super T6, ? super T7, ? super T8, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2, s3, s4, s5, s6, s7, s8}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1], (T3) args[2], (T4) args[3], (T5) args[4], (T6) args[5], (T7) args[6], (T8) args[7]);
}
});
}
/**
* Returns an Observable that emits the results of a specified combiner function applied to nine items
* emitted by nine other Singles.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T1> the first source Single's value type
* @param <T2> the second source Single's value type
* @param <T3> the third source Single's value type
* @param <T4> the fourth source Single's value type
* @param <T5> the fifth source Single's value type
* @param <T6> the sixth source Single's value type
* @param <T7> the seventh source Single's value type
* @param <T8> the eighth source Single's value type
* @param <T9> the ninth source Single's value type
* @param <R> the result value type
* @param s1
* the first source Single
* @param s2
* a second source Single
* @param s3
* a third source Single
* @param s4
* a fourth source Single
* @param s5
* a fifth source Single
* @param s6
* a sixth source Single
* @param s7
* a seventh source Single
* @param s8
* an eighth source Single
* @param s9
* a ninth source Single
* @param zipFunction
* a function that, when applied to the item emitted by each of the source Singles, results in an
* item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <T1, T2, T3, T4, T5, T6, T7, T8, T9, R> Single<R> zip(Single<? extends T1> s1, Single<? extends T2> s2, Single<? extends T3> s3, Single<? extends T4> s4, Single<? extends T5> s5, Single<? extends T6> s6, Single<? extends T7> s7, Single<? extends T8> s8,
Single<? extends T9> s9, final Func9<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, ? super T6, ? super T7, ? super T8, ? super T9, ? extends R> zipFunction) {
return SingleOperatorZip.zip(new Single[] {s1, s2, s3, s4, s5, s6, s7, s8, s9}, new FuncN<R>() {
@Override
public R call(Object... args) {
return zipFunction.call((T1) args[0], (T2) args[1], (T3) args[2], (T4) args[3], (T5) args[4], (T6) args[5], (T7) args[6], (T8) args[7], (T9) args[8]);
}
});
}
/**
* Returns a Single that emits the result of specified combiner function applied to combination of
* items emitted, in sequence, by an Iterable of other Singles.
* <p>
* {@code zip} applies this function in strict sequence.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zip} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <R> the result value type
* @param singles
* an Iterable of source Singles. Should not be empty because {@link Single} either emits result or error.
* {@link java.util.NoSuchElementException} will be emit as error if Iterable will be empty.
* @param zipFunction
* a function that, when applied to an item emitted by each of the source Singles, results in
* an item that will be emitted by the resulting Single
* @return a Single that emits the zipped results
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("unchecked")
public static <R> Single<R> zip(Iterable<? extends Single<?>> singles, FuncN<? extends R> zipFunction) {
@SuppressWarnings("rawtypes")
Single[] iterableToArray = iterableToArray(singles);
return SingleOperatorZip.zip(iterableToArray, zipFunction);
}
/**
* Returns a Single that subscribes to this Single lazily, caches its success or error event
* and replays it to all the downstream subscribers.
* <p>
* <img width="640" height="410" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/cache.png" alt="">
* <p>
* This is useful when you want a Single to cache its response and you can't control the
* subscribe/unsubscribe behavior of all the {@link Subscriber}s.
* <p>
* The operator subscribes only when the first downstream subscriber subscribes and maintains
* a single subscription towards this Single. In contrast, the operator family of {@link Observable#replay()}
* that return a {@link ConnectableObservable} require an explicit call to {@link ConnectableObservable#connect()}.
* <p>
* <em>Note:</em> You sacrifice the ability to unsubscribe from the origin when you use the {@code cache}
* Observer so be careful not to use this Observer on Observables that emit an infinite or very large number
* of items that will use up memory.
* A possible workaround is to apply `takeUntil` with a predicate or
* another source before (and perhaps after) the application of cache().
* <pre><code>
* AtomicBoolean shouldStop = new AtomicBoolean();
*
* source.takeUntil(v -> shouldStop.get())
* .cache()
* .takeUntil(v -> shouldStop.get())
* .subscribe(...);
* </code></pre>
* Since the operator doesn't allow clearing the cached values either, the possible workaround is
* to forget all references to it via {@link Observable#onTerminateDetach()} applied along with the previous
* workaround:
* <pre><code>
* AtomicBoolean shouldStop = new AtomicBoolean();
*
* source.takeUntil(v -> shouldStop.get())
* .onTerminateDetach()
* .cache()
* .takeUntil(v -> shouldStop.get())
* .onTerminateDetach()
* .subscribe(...);
* </code></pre>
* <dl>
* <dt><b>Backpressure:</b></dt>
* <dd>The operator consumes this Single in an unbounded fashion but respects the backpressure
* of each downstream Subscriber individually.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code cache} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @return a Single that, when first subscribed to, caches its response for the
* benefit of subsequent subscribers
* @see <a href="http://reactivex.io/documentation/operators/replay.html">ReactiveX operators documentation: Replay</a>
* @since 1.3
*/
public final Single<T> cache() {
return toObservable().cacheWithInitialCapacity(1).toSingle();
}
/**
* Returns an Observable that emits the item emitted by the source Single, then the item emitted by the
* specified Single.
* <p>
* <img width="640" height="335" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.concatWith.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code concat} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param t1
* a Single to be concatenated after the current
* @return an Observable that emits the item emitted by the source Single, followed by the item emitted by
* {@code t1}
* @see <a href="http://reactivex.io/documentation/operators/concat.html">ReactiveX operators documentation: Concat</a>
*/
public final Observable<T> concatWith(Single<? extends T> t1) {
return concat(this, t1);
}
/**
* Returns a Single that is based on applying a specified function to the item emitted by the source Single,
* where that function returns a Single.
* <p>
* <img width="640" height="300" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMap.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code flatMap} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <R> the result value type
* @param func
* a function that, when applied to the item emitted by the source Single, returns a Single
* @return the Single returned from {@code func} when applied to the item emitted by the source Single
* @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
*/
public final <R> Single<R> flatMap(final Func1<? super T, ? extends Single<? extends R>> func) {
if (this instanceof ScalarSynchronousSingle) {
return ((ScalarSynchronousSingle<T>) this).scalarFlatMap(func);
}
return merge(map(func));
}
/**
* Returns an Observable that emits items based on applying a specified function to the item emitted by the
* source Observable, where that function returns an Observable.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMapObservable.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code flatMapObservable} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <R> the result value type
* @param func
* a function that, when applied to the item emitted by the source Single, returns an
* Observable
* @return the Observable returned from {@code func} when applied to the item emitted by the source Single
* @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
*/
public final <R> Observable<R> flatMapObservable(Func1<? super T, ? extends Observable<? extends R>> func) {
return Observable.merge(asObservable(map(func)));
}
/**
* Returns a {@link Completable} that completes based on applying a specified function to the item emitted by the
* source {@link Completable}, where that function returns a {@link Completable}.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.flatMapCompletable.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code flatMapCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param func
* a function that, when applied to the item emitted by the source Single, returns a
* Completable
* @return the Completable returned from {@code func} when applied to the item emitted by the source Single
* @see <a href="http://reactivex.io/documentation/operators/flatmap.html">ReactiveX operators documentation: FlatMap</a>
* @since 1.3
*/
public final Completable flatMapCompletable(final Func1<? super T, ? extends Completable> func) {
return Completable.create(new CompletableFlatMapSingleToCompletable<T>(this, func));
}
/**
* Returns a Single that applies a specified function to the item emitted by the source Single and
* emits the result of this function application.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.map.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code map} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <R> the result value type
* @param func
* a function to apply to the item emitted by the Single
* @return a Single that emits the item from the source Single, transformed by the specified function
* @see <a href="http://reactivex.io/documentation/operators/map.html">ReactiveX operators documentation: Map</a>
*/
public final <R> Single<R> map(Func1<? super T, ? extends R> func) {
return create(new SingleOnSubscribeMap<T, R>(this, func));
}
/**
* Flattens this and another Single into a single Observable, without any transformation.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.merge.png" alt="">
* <p>
* You can combine items emitted by multiple Singles so that they appear as a single Observable, by using
* the {@code mergeWith} method.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code mergeWith} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param t1
* a Single to be merged
* @return an Observable that emits all of the items emitted by the source Singles
* @see <a href="http://reactivex.io/documentation/operators/merge.html">ReactiveX operators documentation: Merge</a>
*/
public final Observable<T> mergeWith(Single<? extends T> t1) {
return merge(this, t1);
}
/**
* Modifies a Single to emit its item (or notify of its error) on a specified {@link Scheduler},
* asynchronously.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.observeOn.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>you specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param scheduler
* the {@link Scheduler} to notify subscribers on
* @return the source Single modified so that its subscribers are notified on the specified
* {@link Scheduler}
* @see <a href="http://reactivex.io/documentation/operators/observeon.html">ReactiveX operators documentation: ObserveOn</a>
* @see <a href="http://www.grahamlea.com/2014/07/rxjava-threading-examples/">RxJava Threading Examples</a>
* @see #subscribeOn
*/
public final Single<T> observeOn(Scheduler scheduler) {
if (this instanceof ScalarSynchronousSingle) {
return ((ScalarSynchronousSingle<T>)this).scalarScheduleOn(scheduler);
}
if (scheduler == null) {
throw new NullPointerException("scheduler is null");
}
return create(new SingleObserveOn<T>(onSubscribe, scheduler));
}
/**
* Instructs a Single to emit an item (returned by a specified function) rather than invoking
* {@link SingleSubscriber#onError onError} if it encounters an error.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.onErrorReturn.png" alt="">
* <p>
* By default, when a Single encounters an error that prevents it from emitting the expected item to its
* subscriber, the Single invokes its subscriber's {@link Subscriber#onError} method, and then quits
* without invoking any more of its subscriber's methods. The {@code onErrorReturn} method changes this
* behavior. If you pass a function ({@code resumeFunction}) to a Single's {@code onErrorReturn} method, if
* the original Single encounters an error, instead of invoking its subscriber's
* {@link Subscriber#onError} method, it will instead emit the return value of {@code resumeFunction}.
* <p>
* You can use this to prevent errors from propagating or to supply fallback data should errors be
* encountered.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code onErrorReturn} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param resumeFunction
* a function that returns an item that the new Single will emit if the source Single encounters
* an error
* @return the original Single with appropriately modified behavior
* @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
*/
public final Single<T> onErrorReturn(Func1<Throwable, ? extends T> resumeFunction) {
return create(new SingleOnErrorReturn<T>(onSubscribe, resumeFunction));
}
/**
* Instructs a Single to pass control to another Single rather than invoking
* {@link Observer#onError(Throwable)} if it encounters an error.
* <p/>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onErrorResumeNext.png" alt="">
* <p/>
* By default, when a Single encounters an error that prevents it from emitting the expected item to
* its {@link Observer}, the Single invokes its Observer's {@code onError} method, and then quits
* without invoking any more of its Observer's methods. The {@code onErrorResumeNext} method changes this
* behavior. If you pass another Single ({@code resumeSingleInCaseOfError}) to a Single's
* {@code onErrorResumeNext} method, if the original Single encounters an error, instead of invoking its
* Observer's {@code onError} method, it will instead relinquish control to {@code resumeSingleInCaseOfError} which
* will invoke the Observer's {@link Observer#onNext onNext} method if it is able to do so. In such a case,
* because no Single necessarily invokes {@code onError}, the Observer may never know that an error
* happened.
* <p/>
* You can use this to prevent errors from propagating or to supply fallback data should errors be
* encountered.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code onErrorResumeNext} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param resumeSingleInCaseOfError a Single that will take control if source Single encounters an error.
* @return the original Single, with appropriately modified behavior.
* @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
* @since 1.3
*/
public final Single<T> onErrorResumeNext(Single<? extends T> resumeSingleInCaseOfError) {
return new Single<T>(SingleOperatorOnErrorResumeNext.withOther(this, resumeSingleInCaseOfError));
}
/**
* Instructs a Single to pass control to another Single rather than invoking
* {@link Observer#onError(Throwable)} if it encounters an error.
* <p/>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/onErrorResumeNext.png" alt="">
* <p/>
* By default, when a Single encounters an error that prevents it from emitting the expected item to
* its {@link Observer}, the Single invokes its Observer's {@code onError} method, and then quits
* without invoking any more of its Observer's methods. The {@code onErrorResumeNext} method changes this
* behavior. If you pass a function that will return another Single ({@code resumeFunctionInCaseOfError}) to a Single's
* {@code onErrorResumeNext} method, if the original Single encounters an error, instead of invoking its
* Observer's {@code onError} method, it will instead relinquish control to {@code resumeSingleInCaseOfError} which
* will invoke the Observer's {@link Observer#onNext onNext} method if it is able to do so. In such a case,
* because no Single necessarily invokes {@code onError}, the Observer may never know that an error
* happened.
* <p/>
* You can use this to prevent errors from propagating or to supply fallback data should errors be
* encountered.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code onErrorResumeNext} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param resumeFunctionInCaseOfError a function that returns a Single that will take control if source Single encounters an error.
* @return the original Single, with appropriately modified behavior.
* @see <a href="http://reactivex.io/documentation/operators/catch.html">ReactiveX operators documentation: Catch</a>
* @since 1.3
*/
public final Single<T> onErrorResumeNext(final Func1<Throwable, ? extends Single<? extends T>> resumeFunctionInCaseOfError) {
return new Single<T>(SingleOperatorOnErrorResumeNext.withFunction(this, resumeFunctionInCaseOfError));
}
/**
* Subscribes to a Single but ignore its emission or notification.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code subscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @return a {@link Subscription} reference can request the {@link Single} stop work.
* @throws OnErrorNotImplementedException
* if the Single tries to call {@link Subscriber#onError}
* @see <a href="http://reactivex.io/documentation/operators/subscribe.html">ReactiveX operators documentation: Subscribe</a>
*/
public final Subscription subscribe() {
return subscribe(Actions.empty(), Actions.errorNotImplemented());
}
/**
* Subscribes to a Single and provides a callback to handle the item it emits.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code subscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param onSuccess
* the {@code Action1<T>} you have designed to accept the emission from the Single
* @return a {@link Subscription} reference can request the {@link Single} stop work.
* @throws IllegalArgumentException
* if {@code onNext} is null
* @throws OnErrorNotImplementedException
* if the Single tries to call {@link Subscriber#onError}
* @see <a href="http://reactivex.io/documentation/operators/subscribe.html">ReactiveX operators documentation: Subscribe</a>
*/
public final Subscription subscribe(final Action1<? super T> onSuccess) {
return subscribe(onSuccess, Actions.errorNotImplemented());
}
/**
* Subscribes to a Single and provides callbacks to handle the item it emits or any error notification it
* issues.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code subscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param onSuccess
* the {@code Action1<T>} you have designed to accept the emission from the Single
* @param onError
* the {@code Action1<Throwable>} you have designed to accept any error notification from the
* Single
* @return a {@link Subscription} reference can request the {@link Single} stop work.
* @see <a href="http://reactivex.io/documentation/operators/subscribe.html">ReactiveX operators documentation: Subscribe</a>
* @throws IllegalArgumentException
* if {@code onNext} is null, or
* if {@code onError} is null
*/
public final Subscription subscribe(final Action1<? super T> onSuccess, final Action1<Throwable> onError) {
if (onSuccess == null) {
throw new IllegalArgumentException("onSuccess can not be null");
}
if (onError == null) {
throw new IllegalArgumentException("onError can not be null");
}
return subscribe(new SingleSubscriber<T>() {
@Override
public final void onError(Throwable e) {
try {
onError.call(e);
} finally {
unsubscribe();
}
}
@Override
public final void onSuccess(T args) {
try {
onSuccess.call(args);
} finally {
unsubscribe();
}
}
});
}
/**
* Subscribes to a Single and invokes the {@link OnSubscribe} function without any contract protection,
* error handling, unsubscribe, or execution hooks.
* <p>
* Use this only for implementing an {@link Operator} that requires nested subscriptions. For other
* purposes, use {@link #subscribe(Subscriber)} which ensures the Rx contract and other functionality.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code unsafeSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param subscriber
* the Subscriber that will handle the emission or notification from the Single
* @return the subscription that allows unsubscribing
*/
public final Subscription unsafeSubscribe(Subscriber<? super T> subscriber) {
return unsafeSubscribe(subscriber, true);
}
private Subscription unsafeSubscribe(Subscriber<? super T> subscriber, boolean start) {
try {
if (start) {
// new Subscriber so onStart it
subscriber.onStart();
}
RxJavaHooks.onSingleStart(this, onSubscribe).call(SingleLiftObservableOperator.wrap(subscriber));
return RxJavaHooks.onSingleReturn(subscriber);
} catch (Throwable e) {
// special handling for certain Throwable/Error/Exception types
Exceptions.throwIfFatal(e);
// if an unhandled error occurs executing the onSubscribe we will propagate it
try {
subscriber.onError(RxJavaHooks.onSingleError(e));
} catch (Throwable e2) {
Exceptions.throwIfFatal(e2);
// if this happens it means the onError itself failed (perhaps an invalid function implementation)
// so we are unable to propagate the error correctly and will just throw
RuntimeException r = new RuntimeException("Error occurred attempting to subscribe [" + e.getMessage() + "] and then again while trying to pass to onError.", e2);
// TODO could the hook be the cause of the error in the on error handling.
RxJavaHooks.onSingleError(r);
// TODO why aren't we throwing the hook's return value.
throw r; // NOPMD
}
return Subscriptions.unsubscribed();
}
}
/**
* Subscribes an Observer to this single and returns a Subscription that allows
* unsubscription.
*
* @param observer the Observer to subscribe
* @return the Subscription that allows unsubscription
*/
public final Subscription subscribe(final Observer<? super T> observer) {
if (observer == null) {
throw new NullPointerException("observer is null");
}
return subscribe(new SingleSubscriber<T>() {
@Override
public void onSuccess(T value) {
observer.onNext(value);
observer.onCompleted();
}
@Override
public void onError(Throwable error) {
observer.onError(error);
}
});
}
/**
* Subscribes to a Single and provides a Subscriber that implements functions to handle the item the Single
* emits or any error notification it issues.
* <p>
* A typical implementation of {@code subscribe} does the following:
* <ol>
* <li>It stores a reference to the Subscriber in a collection object, such as a {@code List<T>} object.</li>
* <li>It returns a reference to the {@link Subscription} interface. This enables Subscribers to
* unsubscribe, that is, to stop receiving the item or notification before the Single completes.</li>
* </ol><p>
* A {@code Single<T>} instance is responsible for accepting all subscriptions and notifying all
* Subscribers. Unless the documentation for a particular {@code Single<T>} implementation indicates
* otherwise, Subscribers should make no assumptions about the order in which multiple Subscribers will
* receive their notifications.
* <p>
* For more information see the
* <a href="http://reactivex.io/documentation/observable.html">ReactiveX documentation</a>.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code subscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param subscriber
* the {@link Subscriber} that will handle the emission or notification from the Single
* @return a {@link Subscription} reference can request the {@link Single} stop work.
* @throws IllegalStateException
* if {@code subscribe} is unable to obtain an {@code OnSubscribe<>} function
* @throws IllegalArgumentException
* if the {@link Subscriber} provided as the argument to {@code subscribe} is {@code null}
* @throws OnErrorNotImplementedException
* if the {@link Subscriber}'s {@code onError} method is null
* @throws RuntimeException
* if the {@link Subscriber}'s {@code onError} method itself threw a {@code Throwable}
* @see <a href="http://reactivex.io/documentation/operators/subscribe.html">ReactiveX operators documentation: Subscribe</a>
*/
public final Subscription subscribe(Subscriber<? super T> subscriber) {
// validate and proceed
if (subscriber == null) {
throw new IllegalArgumentException("observer can not be null");
}
// new Subscriber so onStart it
subscriber.onStart();
/*
* See https://github.com/ReactiveX/RxJava/issues/216 for discussion on "Guideline 6.4: Protect calls
* to user code from within an Observer"
*/
// if not already wrapped
if (!(subscriber instanceof SafeSubscriber)) {
// assign to `observer` so we return the protected version
return unsafeSubscribe(new SafeSubscriber<T>(subscriber), false);
}
return unsafeSubscribe(subscriber, true);
}
/**
* Subscribes to a Single and provides a {@link SingleSubscriber} that implements functions to handle the
* item the Single emits or any error notification it issues.
* <p>
* A typical implementation of {@code subscribe} does the following:
* <ol>
* <li>It stores a reference to the Subscriber in a collection object, such as a {@code List<T>} object.</li>
* <li>It returns a reference to the {@link Subscription} interface. This enables Subscribers to
* unsubscribe, that is, to stop receiving the item or notification before the Single completes.</li>
* </ol><p>
* A {@code Single<T>} instance is responsible for accepting all subscriptions and notifying all
* Subscribers. Unless the documentation for a particular {@code Single<T>} implementation indicates
* otherwise, Subscribers should make no assumptions about the order in which multiple Subscribers will
* receive their notifications.
* <p>
* For more information see the
* <a href="http://reactivex.io/documentation/observable.html">ReactiveX documentation</a>.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code subscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param te
* the {@link SingleSubscriber} that will handle the emission or notification from the Single
* @return a {@link Subscription} reference can request the {@link Single} stop work.
* @throws IllegalStateException
* if {@code subscribe} is unable to obtain an {@code OnSubscribe<>} function
* @throws IllegalArgumentException
* if the {@link SingleSubscriber} provided as the argument to {@code subscribe} is {@code null}
* @throws OnErrorNotImplementedException
* if the {@link SingleSubscriber}'s {@code onError} method is null
* @throws RuntimeException
* if the {@link SingleSubscriber}'s {@code onError} method itself threw a {@code Throwable}
* @see <a href="http://reactivex.io/documentation/operators/subscribe.html">ReactiveX operators documentation: Subscribe</a>
*/
public final Subscription subscribe(final SingleSubscriber<? super T> te) {
if (te == null) {
throw new IllegalArgumentException("te is null");
}
try {
RxJavaHooks.onSingleStart(this, onSubscribe).call(te);
return RxJavaHooks.onSingleReturn(te);
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
// if an unhandled error occurs executing the onSubscribe we will propagate it
try {
te.onError(RxJavaHooks.onSingleError(ex));
} catch (Throwable e2) {
Exceptions.throwIfFatal(e2);
// if this happens it means the onError itself failed (perhaps an invalid function implementation)
// so we are unable to propagate the error correctly and will just throw
RuntimeException r = new RuntimeException("Error occurred attempting to subscribe [" + ex.getMessage() + "] and then again while trying to pass to onError.", e2);
// TODO could the hook be the cause of the error in the on error handling.
RxJavaHooks.onSingleError(r);
// TODO why aren't we throwing the hook's return value.
throw r; // NOPMD
}
return Subscriptions.empty();
}
}
/**
* Asynchronously subscribes subscribers to this Single on the specified {@link Scheduler}.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.subscribeOn.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>you specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param scheduler
* the {@link Scheduler} to perform subscription actions on
* @return the source Single modified so that its subscriptions happen on the specified {@link Scheduler}
* @see <a href="http://reactivex.io/documentation/operators/subscribeon.html">ReactiveX operators documentation: SubscribeOn</a>
* @see <a href="http://www.grahamlea.com/2014/07/rxjava-threading-examples/">RxJava Threading Examples</a>
* @see #observeOn
*/
public final Single<T> subscribeOn(final Scheduler scheduler) {
if (this instanceof ScalarSynchronousSingle) {
return ((ScalarSynchronousSingle<T>)this).scalarScheduleOn(scheduler);
}
return create(new OnSubscribe<T>() {
@Override
public void call(final SingleSubscriber<? super T> t) {
final Scheduler.Worker w = scheduler.createWorker();
t.add(w);
w.schedule(new Action0() {
@Override
public void call() {
SingleSubscriber<T> single = new SingleSubscriber<T>() {
@Override
public void onSuccess(T value) {
try {
t.onSuccess(value);
} finally {
w.unsubscribe();
}
}
@Override
public void onError(Throwable error) {
try {
t.onError(error);
} finally {
w.unsubscribe();
}
}
};
t.add(single);
Single.this.subscribe(single);
}
});
}
});
}
/**
* Returns a Single that emits the item emitted by the source Single until a Completable terminates. Upon
* termination of {@code other}, this will emit a {@link CancellationException} rather than go to
* {@link SingleSubscriber#onSuccess(Object)}.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/takeUntil.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code takeUntil} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param other
* the Completable whose termination will cause {@code takeUntil} to emit the item from the source
* Single
* @return a Single that emits the item emitted by the source Single until such time as {@code other} terminates.
* @see <a href="http://reactivex.io/documentation/operators/takeuntil.html">ReactiveX operators documentation: TakeUntil</a>
*/
public final Single<T> takeUntil(final Completable other) {
return create(new SingleTakeUntilCompletable<T>(onSubscribe, other));
}
/**
* Returns a Single that emits the item emitted by the source Single until an Observable emits an item. Upon
* emission of an item from {@code other}, this will emit a {@link CancellationException} rather than go to
* {@link SingleSubscriber#onSuccess(Object)}.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/takeUntil.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code takeUntil} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param other
* the Observable whose first emitted item will cause {@code takeUntil} to emit the item from the source
* Single
* @param <E>
* the type of items emitted by {@code other}
* @return a Single that emits the item emitted by the source Single until such time as {@code other} emits
* its first item
* @see <a href="http://reactivex.io/documentation/operators/takeuntil.html">ReactiveX operators documentation: TakeUntil</a>
*/
public final <E> Single<T> takeUntil(final Observable<? extends E> other) {
return create(new SingleTakeUntilObservable<T, E>(onSubscribe, other));
}
/**
* Returns a Single that emits the item emitted by the source Single until a second Single emits an item. Upon
* emission of an item from {@code other}, this will emit a {@link CancellationException} rather than go to
* {@link SingleSubscriber#onSuccess(Object)}.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/takeUntil.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code takeUntil} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param other
* the Single whose emitted item will cause {@code takeUntil} to emit the item from the source Single
* @param <E>
* the type of item emitted by {@code other}
* @return a Single that emits the item emitted by the source Single until such time as {@code other} emits its item
* @see <a href="http://reactivex.io/documentation/operators/takeuntil.html">ReactiveX operators documentation: TakeUntil</a>
*/
public final <E> Single<T> takeUntil(final Single<? extends E> other) {
return create(new SingleTakeUntilSingle<T, E>(onSubscribe, other));
}
/**
* Calls the specified converter function during assembly time and returns its resulting value.
* <p>
* This allows fluent conversion to any other type.
* @param <R> the resulting object type
* @param converter the function that receives the current Single instance and returns a value
* @return the value returned by the function
* @since 1.3
*/
public final <R> R to(Func1<? super Single<T>, R> converter) {
return converter.call(this);
}
/**
* Converts this Single into an {@link Observable}.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.toObservable.png" alt="">
*
* @return an {@link Observable} that emits a single item T.
*/
public final Observable<T> toObservable() {
return asObservable(this);
}
/**
* Returns a {@link Completable} that discards result of the {@link Single} (similar to
* {@link Observable#ignoreElements()}) and calls {@code onCompleted} when this source {@link Single} calls
* {@code onSuccess}. Error terminal event is propagated.
* <p>
* <img width="640" height="295" src=
* "https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.toCompletable.png"
* alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code toCompletable} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @return a {@link Completable} that calls {@code onCompleted} on it's subscriber when the source {@link Single}
* calls {@code onSuccess}.
* @see <a href="http://reactivex.io/documentation/completable.html">ReactiveX documentation: Completable</a>
* @since 1.3
*/
public final Completable toCompletable() {
return Completable.fromSingle(this);
}
/**
* Returns a Single that mirrors the source Single but applies a timeout policy for its emitted item. If it
* is not emitted within the specified timeout duration, the resulting Single terminates and notifies
* subscribers of a {@code TimeoutException}.
* <p>
* <img width="640" height="300" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeout.1.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This version of {@code timeout} operates by default on the {@code computation} {@link Scheduler}.</dd>
* </dl>
*
* @param timeout
* maximum duration before the Single times out
* @param timeUnit
* the unit of time that applies to the {@code timeout} argument.
* @return the source Single modified to notify subscribers of a {@code TimeoutException} in case of a
* timeout
* @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
*/
public final Single<T> timeout(long timeout, TimeUnit timeUnit) {
return timeout(timeout, timeUnit, null, Schedulers.computation());
}
/**
* Returns a Single that mirrors the source Single but applies a timeout policy for its emitted item, where
* this policy is governed on a specified Scheduler. If the item is not emitted within the specified timeout
* duration, the resulting Single terminates and notifies subscribers of a {@code TimeoutException}.
* <p>
* <img width="640" height="300" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeout.1s.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>you specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param timeout
* maximum duration before the Single times out
* @param timeUnit
* the unit of time that applies to the {@code timeout} argument
* @param scheduler
* the Scheduler to run the timeout timers on
* @return the source Single modified to notify subscribers of a {@code TimeoutException} in case of a
* timeout
* @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
*/
public final Single<T> timeout(long timeout, TimeUnit timeUnit, Scheduler scheduler) {
return timeout(timeout, timeUnit, null, scheduler);
}
/**
* Returns a Single that mirrors the source Single but applies a timeout policy for its emitted item. If it
* is not emitted within the specified timeout duration, the resulting Single instead mirrors a fallback
* Single.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeout.2.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This version of {@code timeout} operates by default on the {@code computation} {@link Scheduler}.</dd>
* </dl>
*
* @param timeout
* maximum time before a timeout occurs
* @param timeUnit
* the unit of time that applies to the {@code timeout} argument
* @param other
* the fallback Single to use in case of a timeout
* @return the source Single modified to switch to the fallback Single in case of a timeout
* @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
*/
public final Single<T> timeout(long timeout, TimeUnit timeUnit, Single<? extends T> other) {
return timeout(timeout, timeUnit, other, Schedulers.computation());
}
/**
* Returns a Single that mirrors the source Single but applies a timeout policy for its emitted item, using
* a specified Scheduler. If the item isn't emitted within the specified timeout duration, the resulting
* Single instead mirrors a fallback Single.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.timeout.2s.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>you specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param timeout
* maximum duration before a timeout occurs
* @param timeUnit
* the unit of time that applies to the {@code timeout} argument
* @param other
* the Single to use as the fallback in case of a timeout
* @param scheduler
* the {@link Scheduler} to run the timeout timers on
* @return the source Single modified so that it will switch to the fallback Single in case of a timeout
* @see <a href="http://reactivex.io/documentation/operators/timeout.html">ReactiveX operators documentation: Timeout</a>
*/
public final Single<T> timeout(long timeout, TimeUnit timeUnit, Single<? extends T> other, Scheduler scheduler) {
if (other == null) {
// Use a defer instead of simply other = Single.error(new TimeoutException())
// since instantiating an exception will cause the current stack trace to be inspected
// and we only want to incur that overhead when a timeout actually happens.
other = Single.<T>defer(new Func0<Single<T>>() {
@Override
public Single<T> call() {
return Single.<T>error(new TimeoutException());
}
});
}
return create(new SingleTimeout<T>(onSubscribe, timeout, timeUnit, scheduler, other.onSubscribe));
}
/**
* Converts a Single into a {@link BlockingSingle} (a Single with blocking operators).
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code toBlocking} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @return a {@code BlockingSingle} version of this Single.
* @see <a href="http://reactivex.io/documentation/operators/to.html">ReactiveX operators documentation: To</a>
* @since 1.3
*/
public final BlockingSingle<T> toBlocking() {
return BlockingSingle.from(this);
}
/**
* Returns a Single that emits the result of applying a specified function to the pair of items emitted by
* the source Single and another specified Single.
* <p>
* <img width="640" height="380" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.zip.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code zipWith} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T2>
* the type of items emitted by the {@code other} Single
* @param <R>
* the type of items emitted by the resulting Single
* @param other
* the other Observable
* @param zipFunction
* a function that combines the pairs of items from the two Observables to generate the items to
* be emitted by the resulting Single
* @return an Observable that pairs up values from the source Observable and the {@code other} Observable
* and emits the results of {@code zipFunction} applied to these pairs
* @see <a href="http://reactivex.io/documentation/operators/zip.html">ReactiveX operators documentation: Zip</a>
*/
@SuppressWarnings("cast")
public final <T2, R> Single<R> zipWith(Single<? extends T2> other, Func2<? super T, ? super T2, ? extends R> zipFunction) {
return (Single<R>)zip(this, other, zipFunction);
}
/**
* Modifies the source {@link Single} so that it invokes an action if it calls {@code onError}.
* <p>
* In case the onError action throws, the downstream will receive a composite exception containing
* the original exception and the exception thrown by onError.
* <p>
* <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnError.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code doOnError} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param onError
* the action to invoke if the source {@link Single} calls {@code onError}
* @return the source {@link Single} with the side-effecting behavior applied
* @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
* @since 1.3
*/
public final Single<T> doOnError(final Action1<Throwable> onError) {
if (onError == null) {
throw new IllegalArgumentException("onError is null");
}
return Single.create(new SingleDoOnEvent<T>(this, Actions.empty(), new Action1<Throwable>() {
@Override
public void call(final Throwable throwable) {
onError.call(throwable);
}
}));
}
/**
* Modifies the source {@link Single} so that it invokes an action when it calls {@code onSuccess} or {@code onError}.
* <p>
* <img width="640" height="310" src="https://raw.githubusercontent.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnEach.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code doOnEach} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param onNotification
* the action to invoke when the source {@link Single} calls {@code onSuccess} or {@code onError}.
* @return the source {@link Single} with the side-effecting behavior applied
* @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
* @since 1.3
*/
public final Single<T> doOnEach(final Action1<Notification<? extends T>> onNotification) {
if (onNotification == null) {
throw new IllegalArgumentException("onNotification is null");
}
return Single.create(new SingleDoOnEvent<T>(this, new Action1<T>() {
@Override
public void call(final T t) {
onNotification.call(Notification.<T>createOnNext(t));
}
}, new Action1<Throwable>() {
@Override
public void call(final Throwable throwable) {
onNotification.call(Notification.<T>createOnError(throwable));
}
}));
}
/**
* Modifies the source {@link Single} so that it invokes an action when it calls {@code onSuccess}.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnNext.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code doOnSuccess} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param onSuccess
* the action to invoke when the source {@link Single} calls {@code onSuccess}
* @return the source {@link Single} with the side-effecting behavior applied
* @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
* @since 1.3
*/
public final Single<T> doOnSuccess(final Action1<? super T> onSuccess) {
if (onSuccess == null) {
throw new IllegalArgumentException("onSuccess is null");
}
Action1<Throwable> empty = Actions.empty();
return Single.create(new SingleDoOnEvent<T>(this, onSuccess, empty));
}
/**
* Modifies the source {@code Single} so that it invokes the given action when it is subscribed from
* its subscribers. Each subscription will result in an invocation of the given action except when the
* source {@code Single} is reference counted, in which case the source {@code Single} will invoke
* the given action for the first subscription.
* <p>
* <img width="640" height="390" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnSubscribe.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code doOnSubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param subscribe
* the action that gets called when an observer subscribes to this {@code Single}
* @return the source {@code Single} modified so as to call this Action when appropriate
* @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
* @since 1.3
*/
public final Single<T> doOnSubscribe(final Action0 subscribe) {
return create(new SingleDoOnSubscribe<T>(onSubscribe, subscribe));
}
/**
* Returns a Single that emits the items emitted by the source Single shifted forward in time by a
* specified delay. Error notifications from the source Single are not delayed.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.s.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>you specify which {@link Scheduler} this operator will use</dd>
* </dl>
*
* @param delay
* the delay to shift the source by
* @param unit
* the time unit of {@code delay}
* @param scheduler
* the {@link Scheduler} to use for delaying
* @return the source Single shifted in time by the specified delay
* @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
* @since 1.3
*/
public final Single<T> delay(long delay, TimeUnit unit, Scheduler scheduler) {
return create(new SingleDelay<T>(onSubscribe, delay, unit, scheduler));
}
/**
* Returns a Single that emits the items emitted by the source Single shifted forward in time by a
* specified delay. Error notifications from the source Observable are not delayed.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/delay.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This version of {@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
* </dl>
*
* @param delay
* the delay to shift the source by
* @param unit
* the {@link TimeUnit} in which {@code period} is defined
* @return the source Single shifted in time by the specified delay
* @see <a href="http://reactivex.io/documentation/operators/delay.html">ReactiveX operators documentation: Delay</a>
* @since 1.3
*/
public final Single<T> delay(long delay, TimeUnit unit) {
return delay(delay, unit, Schedulers.computation());
}
/**
* Returns a {@link Single} that calls a {@link Single} factory to create a {@link Single} for each new Observer
* that subscribes. That is, for each subscriber, the actual {@link Single} that subscriber observes is
* determined by the factory function.
* <p>
* <img width="640" height="340" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/defer.png" alt="">
* <p>
* The defer Observer allows you to defer or delay emitting value from a {@link Single} until such time as an
* Observer subscribes to the {@link Single}. This allows an {@link Observer} to easily obtain updates or a
* refreshed version of the sequence.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code defer} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param singleFactory
* the {@link Single} factory function to invoke for each {@link Observer} that subscribes to the
* resulting {@link Single}.
* @param <T>
* the type of the items emitted by the {@link Single}.
* @return a {@link Single} whose {@link Observer}s' subscriptions trigger an invocation of the given
* {@link Single} factory function.
* @see <a href="http://reactivex.io/documentation/operators/defer.html">ReactiveX operators documentation: Defer</a>
* @since 1.3
*/
public static <T> Single<T> defer(final Callable<Single<T>> singleFactory) {
return create(new OnSubscribe<T>() {
@Override
public void call(SingleSubscriber<? super T> singleSubscriber) {
Single<? extends T> single;
try {
single = singleFactory.call();
} catch (Throwable t) {
Exceptions.throwIfFatal(t);
singleSubscriber.onError(t);
return;
}
single.subscribe(singleSubscriber);
}
});
}
/**
* Modifies the source {@link Single} so that it invokes the given action when it is unsubscribed from
* its subscribers.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnUnsubscribe.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code doOnUnsubscribe} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param action
* the action that gets called when this {@link Single} is unsubscribed.
* @return the source {@link Single} modified so as to call this Action when appropriate.
* @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
* @since 1.3
*/
public final Single<T> doOnUnsubscribe(final Action0 action) {
return create(new SingleDoOnUnsubscribe<T>(onSubscribe, action));
}
/**
* Registers an {@link Action0} to be called when this {@link Single} invokes either
* {@link SingleSubscriber#onSuccess(Object)} onSuccess} or {@link SingleSubscriber#onError onError}.
* <p>
* <img width="640" height="310" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/finallyDo.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code doAfterTerminate} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param action
* an {@link Action0} to be invoked when the source {@link Single} finishes.
* @return a {@link Single} that emits the same item or error as the source {@link Single}, then invokes the
* {@link Action0}
* @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
* @since 1.3
*/
public final Single<T> doAfterTerminate(Action0 action) {
return create(new SingleDoAfterTerminate<T>(this, action));
}
/**
* FOR INTERNAL USE ONLY.
* <p>
* Converts {@link Iterable} of {@link Single} to array of {@link Single}.
*
* @param singlesIterable
* non null iterable of {@link Single}.
* @return array of {@link Single} with same length as passed iterable.
*/
@SuppressWarnings("unchecked")
static <T> Single<? extends T>[] iterableToArray(final Iterable<? extends Single<? extends T>> singlesIterable) {
Single<? extends T>[] singlesArray;
int count;
if (singlesIterable instanceof Collection) {
Collection<? extends Single<? extends T>> list = (Collection<? extends Single<? extends T>>) singlesIterable;
count = list.size();
singlesArray = list.toArray(new Single[count]);
} else {
Single<? extends T>[] tempArray = new Single[8]; // Magic number used just to reduce number of allocations.
count = 0;
for (Single<? extends T> s : singlesIterable) {
if (count == tempArray.length) {
Single<? extends T>[] sb = new Single[count + (count >> 2)];
System.arraycopy(tempArray, 0, sb, 0, count);
tempArray = sb;
}
tempArray[count] = s;
count++;
}
if (tempArray.length == count) {
singlesArray = tempArray;
} else {
singlesArray = new Single[count];
System.arraycopy(tempArray, 0, singlesArray, 0, count);
}
}
return singlesArray;
}
/**
* Returns a Single that mirrors the source Single, resubscribing to it if it calls {@code onError}
* (infinite retry count).
*
* <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.png" alt="">
*
* If the source Single calls {@link SingleSubscriber#onError}, this method will resubscribe to the source
* Single rather than propagating the {@code onError} call.
*
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code retry} operates by default on the {@code trampoline} {@link Scheduler}.</dd>
* </dl>
*
* @return the source Single modified with retry logic
* @see <a href="http://reactivex.io/documentation/operators/retry.html">ReactiveX operators documentation: Retry</a>
*/
public final Single<T> retry() {
return toObservable().retry().toSingle();
}
/**
* Returns a Single that mirrors the source Single, resubscribing to it if it calls {@code onError}
* up to a specified number of retries.
*
* <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.png" alt="">
*
* If the source Single calls {@link SingleSubscriber#onError}, this method will resubscribe to the source
* Single for a maximum of {@code count} resubscriptions rather than propagating the
* {@code onError} call.
*
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code retry} operates by default on the {@code trampoline} {@link Scheduler}.</dd>
* </dl>
*
* @param count
* number of retry attempts before failing
*
* @return the source Single modified with retry logic
* @see <a href="http://reactivex.io/documentation/operators/retry.html">ReactiveX operators documentation: Retry</a>
*/
public final Single<T> retry(final long count) {
return toObservable().retry(count).toSingle();
}
/**
* Returns a Single that mirrors the source Single, resubscribing to it if it calls {@code onError}
* and the predicate returns true for that specific exception and retry count.
*
* <img width="640" height="315" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retry.png" alt="">
* <dl>
* <dt><b>Backpressure Support:</b></dt>
* <dd>This operator honors backpressure.</td>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code retry} operates by default on the {@code trampoline} {@link Scheduler}.</dd>
* </dl>
*
* @param predicate
* the predicate that determines if a resubscription may happen in case of a specific exception
* and retry count
*
* @return the source Single modified with retry logic
* @see #retry()
* @see <a href="http://reactivex.io/documentation/operators/retry.html">ReactiveX operators documentation: Retry</a>
*/
public final Single<T> retry(Func2<Integer, Throwable, Boolean> predicate) {
return toObservable().retry(predicate).toSingle();
}
/**
* Returns a Single that emits the same values as the source Single with the exception of an
* {@code onError}. An {@code onError} notification from the source will result in the emission of a
* {@link Throwable} item to the Observable provided as an argument to the {@code notificationHandler}
* function.
* <p>Emissions from the handler {@code Observable} is treated as follows:
* <ul>
* <li>If the handler {@code Observable} emits an {@code onCompleted} the {@code retryWhen} will call {@code onError}
* with {@code NoSuchElementException} on the child subscription.</li>
* <li>If the handler {@code Observable} emits an {@code onError} the {@code retryWhen} will call
* {@code onError} with the same Throwable instance on the child subscription.
* <li>Otherwise, the operator will resubscribe to the source Single.</li>
* </ul>
* <p>The {@code notificationHandler} function is called for each subscriber individually. This allows per-Subscriber
* state to be added to the error notification sequence.</p>
* <pre><code>
* single.retryWhen(error -> {
* AtomicInteger counter = new AtomicInteger();
* return error.takeWhile(e -> counter.incrementAndGet() < 3).map(e -> "retry");
* }).subscribe(...);
* </code></pre>
* <p>
* Note that you must compose over the input {@code Observable} provided in the function call because {@link #retryWhen} expects
* an emission of the exception to be matched by an event from the handler Observable.
* <p>
*
* <img width="640" height="430" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/retryWhen.f.png" alt="">
*
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code retryWhen} operates by default on the {@code trampoline} {@link Scheduler}.</dd>
* </dl>
*
* @param notificationHandler
* receives an Observable of notifications with which a user can complete or error, aborting the
* retry
*
* @return the source Single modified with retry logic
* @see <a href="http://reactivex.io/documentation/operators/retry.html">ReactiveX operators documentation: Retry</a>
*/
public final Single<T> retryWhen(final Func1<Observable<? extends Throwable>, ? extends Observable<?>> notificationHandler) {
return toObservable().retryWhen(notificationHandler).toSingle();
}
/**
* Constructs a Single that creates a dependent resource object which is disposed of on unsubscription.
* <p>
* <img width="640" height="400" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/using.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code using} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the value type of the generated source
* @param <Resource> the type of the per-subscriber resource
* @param resourceFactory
* the factory function to create a resource object that depends on the Single
* @param singleFactory
* the factory function to create a Single
* @param disposeAction
* the function that will dispose of the resource
* @return the Single whose lifetime controls the lifetime of the dependent resource object
* @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
* @since 1.3
*/
public static <T, Resource> Single<T> using(
final Func0<Resource> resourceFactory,
final Func1<? super Resource, ? extends Single<? extends T>> singleFactory,
final Action1<? super Resource> disposeAction) {
return using(resourceFactory, singleFactory, disposeAction, false);
}
/**
* Constructs a Single that creates a dependent resource object which is disposed of just before
* termination if you have set {@code disposeEagerly} to {@code true} and unsubscription does not occur
* before termination. Otherwise resource disposal will occur on unsubscription. Eager disposal is
* particularly appropriate for a synchronous Single that reuses resources. {@code disposeAction} will
* only be called once per subscription.
* <p>
* <img width="640" height="400" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/using.png" alt="">
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code using} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param <T> the value type of the generated source
* @param <Resource> the type of the per-subscriber resource
* @param resourceFactory
* the factory function to create a resource object that depends on the Single
* @param singleFactory
* the factory function to create a Single
* @param disposeAction
* the function that will dispose of the resource
* @param disposeEagerly
* if {@code true} then disposal will happen either on unsubscription or just before emission of
* a terminal event ({@code onComplete} or {@code onError}).
* @return the Single whose lifetime controls the lifetime of the dependent resource object
* @see <a href="http://reactivex.io/documentation/operators/using.html">ReactiveX operators documentation: Using</a>
* @since 1.3
*/
public static <T, Resource> Single<T> using(
final Func0<Resource> resourceFactory,
final Func1<? super Resource, ? extends Single<? extends T>> singleFactory,
final Action1<? super Resource> disposeAction, boolean disposeEagerly) {
if (resourceFactory == null) {
throw new NullPointerException("resourceFactory is null");
}
if (singleFactory == null) {
throw new NullPointerException("singleFactory is null");
}
if (disposeAction == null) {
throw new NullPointerException("disposeAction is null");
}
return create(new SingleOnSubscribeUsing<T, Resource>(resourceFactory, singleFactory, disposeAction, disposeEagerly));
}
/**
* Returns a Single that delays the subscription to this Single
* until the Observable completes. In case the {@code onError} of the supplied observer throws,
* the exception will be propagated to the downstream subscriber
* and will result in skipping the subscription of this Single.
*
* <p>
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>This method does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
*
* @param other the Observable that should trigger the subscription
* to this Single.
* @return a Single that delays the subscription to this Single
* until the Observable emits an element or completes normally.
* @since 1.3
*/
public final Single<T> delaySubscription(Observable<?> other) {
if (other == null) {
throw new NullPointerException();
}
return create(new SingleOnSubscribeDelaySubscriptionOther<T>(this, other));
}
/**
* Returns a Single which makes sure when a subscriber cancels the subscription,
* the dispose is called on the specified scheduler
* @param scheduler the target scheduler where to execute the cancellation
* @return the new Single instance
* @since 1.2.8 - experimental
*/
@Experimental
public final Single<T> unsubscribeOn(final Scheduler scheduler) {
return create(new OnSubscribe<T>() {
@Override
public void call(final SingleSubscriber<? super T> t) {
final SingleSubscriber<T> single = new SingleSubscriber<T>() {
@Override
public void onSuccess(T value) {
t.onSuccess(value);
}
@Override
public void onError(Throwable error) {
t.onError(error);
}
};
t.add(Subscriptions.create(new Action0() {
@Override
public void call() {
final Scheduler.Worker w = scheduler.createWorker();
w.schedule(new Action0() {
@Override
public void call() {
try {
single.unsubscribe();
} finally {
w.unsubscribe();
}
}
});
}
}));
Single.this.subscribe(single);
}
});
}
// -------------------------------------------------------------------------
// Fluent test support, super handy and reduces test preparation boilerplate
// -------------------------------------------------------------------------
/**
* Creates an AssertableSubscriber that requests {@code Long.MAX_VALUE} and subscribes
* it to this Observable.
* <dl>
* <dt><b>Backpressure:</b><dt>
* <dd>The returned AssertableSubscriber consumes this Observable in an unbounded fashion.</dd>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code test} does not operate by default on a particular {@link Scheduler}.</dd>
* </dl>
* <p>History: 1.2.3 - experimental
* @return the new AssertableSubscriber instance
* @since 1.3
*/
public final AssertableSubscriber<T> test() {
AssertableSubscriberObservable<T> ts = AssertableSubscriberObservable.create(Long.MAX_VALUE);
subscribe(ts);
return ts;
}
}