How to use Route53 SDK to determine if a domain is available

Using the Java AWS SDK, how can one determine if a subdomain is available. Let's say I have a hosted zone, xyz.com - programatically I would like to generate a custom url, e.g. joe.xyz.cow, but first however determine if the 'joe' has already been taken.

I thought the Route53 SDK would offer a straightforward process to see if a name is in use for a hosted zone but all I've found is a CheckDNSAvailability method of the beanstalk API.