code: public boolean isAvailable(ConversionQuery conversionQuery){
          Objects.requireNonNull(conversionQuery);
          try{
              return conversionQuery.getProviderNames().isEmpty() ||
                      conversionQuery.getProviderNames().contains(getContext().getProviderName());
          }
          catch(Exception e){
              return false;
          }
      }
docs: Checks if an {@link javax.money.convert.ExchangeRate} between two {@link javax.money.CurrencyUnit} is
  available from this provider. This method should check, if a given rate
  is <i>currently</i> defined.
  
  @param conversionQuery the required {@link javax.money.convert.ConversionQuery}, not {@code null}
  @return {@code true}, if such an {@link javax.money.convert.ExchangeRate} is currently
  defined.