getOptionNames method
Returns the names of all parsed option arguments.
Option arguments are those starting with --. For example, given:
--foo=bar --debug
this returns:
['foo', 'debug']
@return a set of option names, or an empty set if none.
Implementation
@override
Set<String> getOptionNames() {
List<String> names = source.getPropertyNames();
return Set.unmodifiable(names.toSet());
}