private <X, Y extends AmazonWebServiceRequest> Response<X> invoke( Request<Y> request, Unmarshaller<X, StaxUnmarshallerContext> unmarshaller, ExecutionContext executionContext) { request.setEndpoint(endpoint); request.setTimeOffset(timeOffset); AmazonWebServiceRequest originalRequest = request.getOriginalRequest(); AWSCredentials credentials = awsCredentialsProvider.getCredentials(); if (originalRequest.getRequestCredentials() != null) { credentials = originalRequest.getRequestCredentials(); } executionContext.setCredentials(credentials); StaxResponseHandler<X> responseHandler = new StaxResponseHandler<X>(unmarshaller); DefaultErrorResponseHandler errorResponseHandler = new DefaultErrorResponseHandler(exceptionUnmarshallers); return client.execute(request, responseHandler, errorResponseHandler, executionContext); }