rx.Emitter Maven / Gradle / Ivy
/**
* Copyright 2016 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 rx.annotations.Experimental;
import rx.functions.Cancellable;
/**
* Abstraction over a RxJava Subscriber that allows associating
* a resource with it and exposes the current number of downstream
* requested amount.
*
* The onNext, onError and onCompleted methods should be called
* in a sequential manner, just like the Observer's methods. The
* other methods are thread-safe.
*
* @param the value type to emit
* @since (if this graduates from Experimental/Beta to supported, replace this parenthetical with the release number)
*/
@Experimental
public interface Emitter extends Observer {
/**
* Sets a Subscription on this emitter; any previous Subscription
* or Cancellation will be unsubscribed/cancelled.
* @param s the subscription, null is allowed
*/
void setSubscription(Subscription s);
/**
* Sets a Cancellable on this emitter; any previous Subscription
* or Cancellation will be unsubscribed/cancelled.
* @param c the cancellable resource, null is allowed
*/
void setCancellation(Cancellable c);
/**
* The current outstanding request amount.
* This method it thread-safe.
* @return the current outstanding request amount
*/
long requested();
/**
* Options to handle backpressure in the emitter.
*/
enum BackpressureMode {
/**
* No backpressure is applied as the onNext calls pass through the Emitter;
* note that this may cause {@link rx.exceptions.MissingBackpressureException} or {@link IllegalStateException}
* somewhere downstream.
*/
NONE,
/**
* Signals a {@link rx.exceptions.MissingBackpressureException} if the downstream can't keep up.
*/
ERROR,
/**
* Buffers (unbounded) all onNext calls until the downstream can consume them.
*/
BUFFER,
/**
* Drops the incoming onNext value if the downstream can't keep up.
*/
DROP,
/**
* Keeps the latest onNext value and overwrites it with newer ones until the downstream
* can consume it.
*/
LATEST
}
}