org.apache.ratis.thirdparty.io.grpc.stub.ClientCallStreamObserver Maven / Gradle / Ivy
Show all versions of ratis-thirdparty-misc
/*
* 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 org.apache.ratis.thirdparty.io.grpc.stub;
import javax.annotation.Nullable;
/**
* A refinement of {@link CallStreamObserver} that allows for lower-level interaction with
* client calls. An instance of this class is obtained via {@link ClientResponseObserver}, or by
* manually casting the {@code StreamObserver} returned by a stub.
*
* 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.
*
*
DO NOT MOCK: The API is too complex to reliably mock. Use InProcessChannelBuilder to create
* "real" RPCs suitable for testing and make a fake for the server-side.
*/
public abstract class ClientCallStreamObserver extends CallStreamObserver {
/**
* Prevent any further processing for this {@code ClientCallStreamObserver}. No further messages
* will be received. The server is informed of cancellations, but may not stop processing the
* call. Cancelling an already
* {@code cancel()}ed {@code ClientCallStreamObserver} has no effect.
*
* No other methods on this class can be called after this method has been called.
*
*
It is recommended that at least one of the arguments to be non-{@code null}, to provide
* useful debug information. Both argument being null may log warnings and result in suboptimal
* performance. Also note that the provided information will not be sent to the server.
*
* @param message if not {@code null}, will appear as the description of the CANCELLED status
* @param cause if not {@code null}, will appear as the cause of the CANCELLED status
*/
public abstract void cancel(@Nullable String message, @Nullable Throwable cause);
/**
* Swaps to manual flow control where no message will be delivered to {@link
* StreamObserver#onNext(Object)} unless it is {@link #request request()}ed. Since {@code
* request()} may not be called before the call is started, a number of initial requests may be
* specified.
*
*
This method may only be called during {@link ClientResponseObserver#beforeStart
* ClientResponseObserver.beforeStart()}.
*/
public void disableAutoRequestWithInitial(int request) {
throw new UnsupportedOperationException();
}
/**
* 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.
*
*
If {@code false}, the runnable passed to {@link #setOnReadyHandler} will be called after
* {@code isReady()} transitions to {@code true}.
*/
@Override
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}.
*
*
May only be called during {@link ClientResponseObserver#beforeStart}.
*
*
Because there is a processing delay to deliver this notification, it is possible for
* concurrent writes to cause {@code isReady() == false} within this callback. Handle "spurious"
* notifications by checking {@code isReady()}'s current value instead of assuming it is now
* {@code true}. If {@code isReady() == false} the normal expectations apply, so there would be
* another {@code onReadyHandler} callback.
*
* @param onReadyHandler to call when peer is ready to receive more messages.
*/
@Override
public abstract void setOnReadyHandler(Runnable onReadyHandler);
/**
* Requests the peer to produce {@code count} more messages to be delivered to the 'inbound'
* {@link StreamObserver}.
*
*
This method is safe to call from multiple threads without external synchronization.
*
* @param count more messages
*/
@Override
public abstract void request(int count);
/**
* Sets message compression for subsequent calls to {@link #onNext}.
*
* @param enable whether to enable compression.
*/
@Override
public abstract void setMessageCompression(boolean enable);
}