public Set<String> getCountryCodes() {
        Set<String> countryCodes = new HashSet<String>();
        for (Entry<String, CurrencyUnit> entry : currenciesByCountry.entrySet()) {
            if (this.equals(entry.getValue())) {
                countryCodes.add(entry.getKey());
            }
        }
        return countryCodes;
    }
public Set < String > getCountryCodes ( ) { Set < String > countryCodes = new HashSet < String > ( ) ; for ( Entry < String , CurrencyUnit > entry : currenciesByCountry . entrySet ( ) ) { if ( this . equals ( entry . getValue ( ) ) ) { countryCodes . add ( entry . getKey ( ) ) ; } } return countryCodes ; }
Gets the country codes applicable to this currency.
<p>
A currency is typically valid in one or more countries.
The codes are typically defined by ISO-3166.
An empty set indicates that no the currency is not associated with a country code.

@return the country codes, may be empty, not null