nl.topicus.jdbc.shaded.com.google.api.gax.rpc.ResponseObserver Maven / Gradle / Ivy
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* Copyright 2017, Google LLC All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google LLC nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package nl.topicus.jdbc.shaded.com.google.api.gax.rpc;
import nl.topicus.jdbc.shaded.com.google.api.core.BetaApi;
/**
* Receives notifications from server-streaming calls.
*
* The application is responsible for implementing the {@code ResponseObserver} and passing it to
* GAX, which then calls the observer with the messages for the application to receive them. The
* methods might be called by different threads, but are guaranteed to happen sequentially. The
* order of callbacks is guaranteed to be:
*
*
* - exactly 1 onStart
*
- 0 or more on Response
*
- exactly 1 onError or onComplete
*
*
* By default, the stream uses automatic flow control, where the next response will be delivered
* as soon as the current one is processed by onResponse. A consumer can disable automatic flow
* control by calling {@code disableAutoInboundFlowControl()} in {@code onStart}. After this, the
* consumer must request responses by calling {@code request()}.
*/
@BetaApi("The surface for streaming is not stable yet and may change in the future.")
public interface ResponseObserver {
/**
* Called before the stream is started.
*
* Allows for disabling flow control and early stream termination via {@code StreamController}.
*
* @param controller The controller for the stream.
*/
void onStart(StreamController controller);
/**
* Receives a value from the stream.
*
*
Can be called many times but is never called after {@link #onError(Throwable)} or {@link
* #onComplete()} are called.
*
*
Clients may may receive 0 or more onResponse callbacks.
*
*
If an exception is thrown by an implementation the caller will terminate the stream by
* calling {@link #onError(Throwable)} with the caught exception as the cause.
*
* @param response the value passed to the stream
*/
void onResponse(V response);
/**
* Receives a terminating error from the stream.
*
*
May only be called once, and if called, it must be the last method called. In particular, if
* an exception is thrown by an implementation of {@code onError}, no further calls to any method
* are allowed.
*
* @param t the error occurred on the stream
*/
void onError(Throwable t);
/**
* Receives a notification of successful stream completion.
*
*
May only be called once, and if called, it must be the last method called. In particular, if
* an exception is thrown by an implementation of {@code onComplete}, no further calls to any
* method are allowed.
*/
void onComplete();
}