Check if files exist in a folder before I tar

[Eric Wood]

What is the easiest way to check if files exist in a folder prior to
attempting to back them up via tar?

Tar fails if I run it asking it to back up files and no files exist. 

        <tar destfile="${backup.dir}/${current.dir}.tar">
            <tarfileset dir="${gen.dir}" >
                <include name="*.*" />
            </tarfileset>
        </tar>

Eric