software.amazon.awssdk.core.async

Interface AsyncResponseTransformer<ResponseT,ReturnT>

Type Parameters:

ResponseT - POJO response type.

ReturnT - Type this response handler produces. I.E. the type you are transforming the response into.

All Known Implementing Classes:

ByteArrayAsyncResponseTransformer, EventStreamAsyncResponseTransformer, FileAsyncResponseTransformer

public interface AsyncResponseTransformer<ResponseT,ReturnT>

Callback interface to handle a streaming asynchronous response.

Method Summary

Modifier and Type	Method and Description
ReturnT	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(ResponseT response) Called when the initial response has been received and the POJO response has been unmarshalled.
static <ResponseT> AsyncResponseTransformer<ResponseT,ResponseBytes<ResponseT>>	toBytes() Creates an AsyncResponseTransformer that writes all content to a byte array.
static <ResponseT> AsyncResponseTransformer<ResponseT,ResponseT>	toFile(File file) Creates an AsyncResponseTransformer that writes all the content to the given file.
static <ResponseT> AsyncResponseTransformer<ResponseT,ResponseT>	toFile(Path path) Creates an AsyncResponseTransformer that writes all the content to the given file.

Method Detail

responseReceived

void responseReceived(ResponseT response)

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.

Parameters:

response - Unmarshalled POJO containing metadata about the streamed data.

onStream

void onStream(SdkPublisher<ByteBuffer> publisher)

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 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.

exceptionOccurred

void exceptionOccurred(Throwable throwable)

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.

Parameters:

throwable - Exception that occurred.

complete

ReturnT complete()

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.

Returns:

Transformed object as a result of the streamed data.

toFile

static <ResponseT> AsyncResponseTransformer<ResponseT,ResponseT> toFile(Path path)

Creates an AsyncResponseTransformer that writes all the content to the given file. In the event of an error, the SDK will attempt to delete the file (whatever has been written to it so far). If the file already exists, an exception will be thrown.

Type Parameters:

ResponseT - Pojo Response type.

Parameters:

path - Path to file to write to.

Returns:

AsyncResponseTransformer instance.

toFile

static <ResponseT> AsyncResponseTransformer<ResponseT,ResponseT> toFile(File file)

Creates an AsyncResponseTransformer that writes all the content to the given file. In the event of an error, the SDK will attempt to delete the file (whatever has been written to it so far). If the file already exists, an exception will be thrown.

Type Parameters:

ResponseT - Pojo Response type.

Parameters:

file - File to write to.

Returns:

AsyncResponseTransformer instance.

toBytes

static <ResponseT> AsyncResponseTransformer<ResponseT,ResponseBytes<ResponseT>> toBytes()

Creates an AsyncResponseTransformer that writes all content to a byte array.

Type Parameters:

ResponseT - Pojo response type.

Returns:

AsyncResponseTransformer instance.