package org.apidesign.apifest08.currency;

/**

 * Interface for exchange rate engine.

 * 

 * @author arnostvalicek

 */

public interface IExchangeRateEngine {

    /**

     * Get exchange rate for conversion from <code>fromCurrency</code> to <code>toCurrency</code>.

     * 

     * @param fromCurrency From currency.

     * @param toCurrency To currency.

     * @return Returns <code>ExchangeRate</code> if exchange rate is known or <code>null</code> if exchanger rate is not known.

     */

    public ExchangeRate getExchangeRate(ConvertorCurrency fromCurrency, ConvertorCurrency toCurrency);

}