public void doStart() throws Exception {
super.doStart();
snsClient = configuration.getAmazonSNSClient() != null
? configuration.getAmazonSNSClient() : createSNSClient();
// creates a new topic, or returns the URL of an existing one
CreateTopicRequest request = new CreateTopicRequest(configuration.getTopicName());
LOG.trace("Creating topic [{}] with request [{}]...", configuration.getTopicName(), request);
CreateTopicResult result = snsClient.createTopic(request);
configuration.setTopicArn(result.getTopicArn());