code: @SuppressWarnings("unchecked")
  	protected HashSet<String> getSetOfStrings(Object strings)
  	{
  		try {
  			return (HashSet<String>) strings;
  		} catch (ClassCastException ex) {
  			Collection<String> list = (Collection<String>) strings;
  			return new HashSet<String>(list);
  		}
  	}
docs: Converts the given object into a set of strings.
  The object must either be a HashSet already, or a different collection type.