/**
* Retrieves a set of the names for all the known files.
*
* @return A set of the names for all the known file.
*/
@Override
public Set<String> getAllFileNames() {
// initialise the set
Set<String> res = new HashSet<String>();
// put the collection of filenames into the set.
res.addAll(database.retrieveAllFilenames());
// return the set.
return res;
}
