package org.apidesign.apifest08.currency;

 /**

  * Convertor factory is a factory class for creating {@link Convertor Convertor}

  * instances.

  *

  * @author jindra

  */

 public final class ConvertorFactory {

     // this class needs no instances

     private ConvertorFactory() {

     }

     /**

      * Create a {@link Convertor Convertor} with given exchange rate

      *

      * @param exchangeRate double reprezenting the exchange rate from primary currency into

      * the secundary currecny

      * @return {@link Convertor Convertor} instance with given exchange rate

      */

     public static Convertor createConvertor(double exchangeRate) {

         if (exchangeRate == 0) {

             throw new IllegalArgumentException("Zero exchange rate is not allowed.");

         }

         return new ConvertorImpl(exchangeRate);

     }

 }