code: public void setDefault(Currency currency) {
          if (currencyList.containsKey(currency.getName())) {
              Common.getInstance().getStorageHandler().getStorageEngine().setDefaultCurrency(currency);
              defaultCurrency = currency;
              currency.setDefault(true);
              for (Map.Entry<String, Currency> currencyEntry : currencyList.entrySet()) {
                  if (!currencyEntry.getValue().equals(currency)) {
                      currency.setDefault(false);
                  }
              }
          }
      }
docs: Set a currency as the default one.
  
  @param currency The currency to set to default