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);

 }