software.amazon.awssdk.awscore.eventstream

Class EventStreamAsyncResponseTransformer<ResponseT,EventT>

java.lang.Object

software.amazon.awssdk.awscore.eventstream.EventStreamAsyncResponseTransformer<ResponseT,EventT>

Type Parameters:

ResponseT - Initial response type of event stream operation.

EventT - Base type of event stream message frames.

All Implemented Interfaces:

AsyncResponseTransformer<SdkResponse,Void>

public class EventStreamAsyncResponseTransformer<ResponseT,EventT>
extends Object
implements AsyncResponseTransformer<SdkResponse,Void>

Unmarshalling layer on top of the AsyncResponseTransformer to decode event stream messages and deliver them to the subscriber.

Constructor Summary

Constructors

Constructor and Description
EventStreamAsyncResponseTransformer(EventStreamResponseHandler<ResponseT,EventT> eventStreamResponseTransformer, HttpResponseHandler<? extends ResponseT> initialResponseUnmarshaller, HttpResponseHandler<? extends EventT> eventUnmarshaller, HttpResponseHandler<? extends Throwable> exceptionUnmarshaller)

Method Summary

Modifier and Type	Method and Description
Void	complete() Called when all data has been successfully published to the Subscriber.
void	exceptionOccurred(Throwable throwable) Called when an exception occurs while establishing the connection or streaming the response.
void	onStream(SdkPublisher<ByteBuffer> publisher) Called when events are ready to be streamed.
void	responseReceived(SdkResponse response) Called when the initial response has been received and the POJO response has been unmarshalled.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface software.amazon.awssdk.core.async.AsyncResponseTransformer

toBytes, toFile, toFile

Constructor Detail

EventStreamAsyncResponseTransformer

public EventStreamAsyncResponseTransformer(EventStreamResponseHandler<ResponseT,EventT> eventStreamResponseTransformer,
                                           HttpResponseHandler<? extends ResponseT> initialResponseUnmarshaller,
                                           HttpResponseHandler<? extends EventT> eventUnmarshaller,
                                           HttpResponseHandler<? extends Throwable> exceptionUnmarshaller)

Parameters:

eventStreamResponseTransformer - Response transformer provided by customer.

initialResponseUnmarshaller - Unmarshaller for the initial-response event stream message.

eventUnmarshaller - Unmarshaller for the various event types.

Method Detail

responseReceived

public void responseReceived(SdkResponse response)

Description copied from interface: AsyncResponseTransformer

Called when the initial response has been received and the POJO response has been unmarshalled. This is guaranteed to be called before onStream.

In the event of a retryable error, this callback may be called multiple times. It also may never be invoked if the request never succeeds.

Specified by:

responseReceived in interface AsyncResponseTransformer<SdkResponse,Void>

Parameters:

response - Unmarshalled POJO containing metadata about the streamed data.

onStream

public void onStream(SdkPublisher<ByteBuffer> publisher)

Description copied from interface: AsyncResponseTransformer

Called when events are ready to be streamed. Implementations must subscribe to the Publisher and request data via a Subscription as they can handle it.

If at any time the subscriber wishes to stop receiving data, it may call Subscription.cancel(). This will be treated as a failure of the response and the AsyncResponseTransformer.exceptionOccurred(Throwable) callback will be invoked.

This callback may never be called if the response has no content or if an error occurs.

In the event of a retryable error, this callback may be called multiple times with different Publishers. If this method is called more than once, implementation must either reset any state to prepare for another stream of data or must throw an exception indicating they cannot reset. If any exception is thrown then no automatic retry is performed.

Specified by:

onStream in interface AsyncResponseTransformer<SdkResponse,Void>

exceptionOccurred

public void exceptionOccurred(Throwable throwable)

Description copied from interface: AsyncResponseTransformer

Called when an exception occurs while establishing the connection or streaming the response. Implementations should free up any resources in this method. This method may be called multiple times during the lifecycle of a request if automatic retries are enabled.

Specified by:

exceptionOccurred in interface AsyncResponseTransformer<SdkResponse,Void>

Parameters:

throwable - Exception that occurred.

complete

public Void complete()

Description copied from interface: AsyncResponseTransformer

Called when all data has been successfully published to the Subscriber. This will only be called once during the lifecycle of the request. Implementors should free up any resources they have opened and do final transformations to produce the return object.

Specified by:

complete in interface AsyncResponseTransformer<SdkResponse,Void>

Returns:

Transformed object as a result of the streamed data.