| /* |
| * Copyright 2016 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.stub; |
| |
| import io.grpc.ExperimentalApi; |
| |
| /** |
| * A refinement of StreamObserver provided by the GRPC runtime to the application that allows for |
| * more complex interactions with call behavior. |
| * |
| * <p>In any call there are logically two {@link StreamObserver} implementations: |
| * <ul> |
| * <li>'inbound' - which the GRPC runtime calls when it receives messages from the |
| * remote peer. This is implemented by the application. |
| * </li> |
| * <li>'outbound' - which the GRPC runtime provides to the application which it uses to |
| * send messages to the remote peer. |
| * </li> |
| * </ul> |
| * |
| * <p>Implementations of this class represent the 'outbound' message stream. |
| * |
| * <p>Like {@code StreamObserver}, implementations are not required to be thread-safe; if multiple |
| * threads will be writing to an instance concurrently, the application must synchronize its calls. |
| * |
| * <p>DO NOT MOCK: The API is too complex to reliably mock. Use InProcessChannelBuilder to create |
| * "real" RPCs suitable for testing. |
| */ |
| @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1788") |
| public abstract class CallStreamObserver<V> implements StreamObserver<V> { |
| |
| /** |
| * If {@code true}, indicates that the observer is capable of sending additional messages |
| * without requiring excessive buffering internally. This value is just a suggestion and the |
| * application is free to ignore it, however doing so may result in excessive buffering within the |
| * observer. |
| */ |
| public abstract boolean isReady(); |
| |
| /** |
| * Set a {@link Runnable} that will be executed every time the stream {@link #isReady()} state |
| * changes from {@code false} to {@code true}. While it is not guaranteed that the same |
| * thread will always be used to execute the {@link Runnable}, it is guaranteed that executions |
| * are serialized with calls to the 'inbound' {@link StreamObserver}. |
| * |
| * <p>On client-side this method may only be called during {@link |
| * ClientResponseObserver#beforeStart}. On server-side it may only be called during the initial |
| * call to the application, before the service returns its {@code StreamObserver}. |
| * |
| * <p>Note that the handler may be called some time after {@link #isReady} has transitioned to |
| * true as other callbacks may still be executing in the 'inbound' observer. |
| * |
| * @param onReadyHandler to call when peer is ready to receive more messages. |
| */ |
| public abstract void setOnReadyHandler(Runnable onReadyHandler); |
| |
| /** |
| * Disables automatic flow control where a token is returned to the peer after a call |
| * to the 'inbound' {@link io.grpc.stub.StreamObserver#onNext(Object)} has completed. If disabled |
| * an application must make explicit calls to {@link #request} to receive messages. |
| * |
| * <p>On client-side this method may only be called during {@link |
| * ClientResponseObserver#beforeStart}. On server-side it may only be called during the initial |
| * call to the application, before the service returns its {@code StreamObserver}. |
| * |
| * <p>Note that for cases where the runtime knows that only one inbound message is allowed |
| * calling this method will have no effect and the runtime will always permit one and only |
| * one message. This is true for: |
| * <ul> |
| * <li>{@link io.grpc.MethodDescriptor.MethodType#UNARY} operations on both the |
| * client and server. |
| * </li> |
| * <li>{@link io.grpc.MethodDescriptor.MethodType#CLIENT_STREAMING} operations on the client. |
| * </li> |
| * <li>{@link io.grpc.MethodDescriptor.MethodType#SERVER_STREAMING} operations on the server. |
| * </li> |
| * </ul> |
| * </p> |
| */ |
| public abstract void disableAutoInboundFlowControl(); |
| |
| /** |
| * Requests the peer to produce {@code count} more messages to be delivered to the 'inbound' |
| * {@link StreamObserver}. |
| * |
| * <p>This method is safe to call from multiple threads without external synchronization. |
| * |
| * @param count more messages |
| */ |
| public abstract void request(int count); |
| |
| /** |
| * Sets message compression for subsequent calls to {@link #onNext}. |
| * |
| * @param enable whether to enable compression. |
| */ |
| public abstract void setMessageCompression(boolean enable); |
| } |