public interface StreamResumptionStrategy<RequestT,ResponseT>
This is part of the server streaming retry api. Its implementers are responsible for tracking the progress of the stream and calculating a request to resume it in case of an error.
Implementations don't have to be threadsafe because all of the calls will be serialized.
public abstract boolean canResume()
If a resume request can be created.
public abstract StreamResumptionStrategy<RequestT,ResponseT> createNew()
Creates a new instance of this StreamResumptionStrategy without accumulated state
public abstract RequestT getResumeRequest(RequestT originalRequest)
Called when a stream needs to be restarted, the implementation should generate a request that will yield a new stream whose first response would come right after the last response received by processResponse.
A request that can be used to resume the stream.
public abstract ResponseT processResponse(ResponseT response)
Called by the
ServerStreamingAttemptCallable when a response has been successfully
received. This method accomplishes two goals:
- It allows the strategy implementation to update its internal state so that it can compose the resume request
- It allows the strategy to alter the incoming responses to adjust for after resume. For example, if the responses are numbered sequentially from the start of the stream, upon resume, the strategy could rewrite the messages to continue the sequence from where it left off. Please note that all messages (even for the first attempt) will be passed through this method.