io.grpc.internal.StreamListener Maven / Gradle / Ivy
/*
* Copyright 2014 The gRPC Authors
*
* 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.grpc.internal;
import java.io.InputStream;
import javax.annotation.Nullable;
/**
* An observer of {@link Stream} events. It is guaranteed to only have one concurrent callback at a
* time.
*/
public interface StreamListener {
/**
* Called upon receiving a message from the remote end-point.
*
* Implementations must eventually drain the provided {@code producer} {@link MessageProducer}
* completely by invoking {@link MessageProducer#next()} to obtain deframed messages until the
* producer returns null.
*
*
This method should return quickly, as the same thread may be used to process other streams.
*
* @param producer supplier of deframed messages.
*/
void messagesAvailable(MessageProducer producer);
/**
* This indicates that the transport is now capable of sending additional messages
* without requiring excessive buffering internally. This event is
* just a suggestion and the application is free to ignore it, however doing so may
* result in excessive buffering within the transport.
*/
void onReady();
/**
* A producer for deframed gRPC messages.
*/
interface MessageProducer {
/**
* Returns the next gRPC message, if the data has been received by the deframer and the
* application has requested another message.
*
*
The provided {@code message} {@link InputStream} must be closed by the listener.
*
*
This is intended to be used similar to an iterator, invoking {@code next()} to obtain
* messages until the producer returns null, at which point the producer may be discarded.
*/
@Nullable
public InputStream next();
}
}