/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License is
* distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
* the License for the specific language governing permissions and limitations under the License.
*/
package io.reactivex;
import io.reactivex.annotations.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.functions.Cancellable;
/**
* Abstraction over a Reactive Streams {@link org.reactivestreams.Subscriber} that allows associating
* a resource with it and exposes the current number of downstream
* requested amount.
* <p>
* The onNext, onError and onComplete methods should be called
* in a sequential manner, just like the Subscriber's methods.
* Use {@link #serialize()} if you want to ensure this.
* The other methods are thread-safe.
*
* @param <T> the value type to emit
*/
public interface FlowableEmitter<T> extends Emitter<T> {
/**
* Sets a Disposable on this emitter; any previous Disposable
* or Cancellation will be disposed/cancelled.
* @param s the disposable, null is allowed
*/
void setDisposable(@Nullable Disposable s);
/**
* Sets a Cancellable on this emitter; any previous Disposable
* or Cancellation will be disposed/cancelled.
* @param c the cancellable resource, null is allowed
*/
void setCancellable(@Nullable Cancellable c);
/**
* The current outstanding request amount.
* <p>This method is thread-safe.
* @return the current outstanding request amount
*/
long requested();
/**
* Returns true if the downstream cancelled the sequence.
* <p>This method is thread-safe.
* @return true if the downstream cancelled the sequence
*/
boolean isCancelled();
/**
* Ensures that calls to onNext, onError and onComplete are properly serialized.
* @return the serialized FlowableEmitter
*/
@NonNull
FlowableEmitter<T> serialize();
/**
* Attempts to emit the specified {@code Throwable} error if the downstream
* hasn't cancelled the sequence or is otherwise terminated, returning false
* if the emission is not allowed to happen due to lifecycle restrictions.
* <p>
* Unlike {@link #onError(Throwable)}, the {@code RxJavaPlugins.onError} is not called
* if the error could not be delivered.
* @param t the throwable error to signal if possible
* @return true if successful, false if the downstream is not able to accept further
* events
* @since 2.1.1 - experimental
*/
@Experimental
boolean tryOnError(@NonNull Throwable t);
}