package org.apidesign.apifest08.currency;

/**

 * Some Factory for Factories :-)

 * Depends on the whole application design...

 * @author Ladislav Vitasek

 */

final public class ConvertorsFactory {

    private CurrencyConvertorFactory currencyConvertorFactoryInstance = null;

    private final static ConvertorsFactory instance = new ConvertorsFactory();

    private ConvertorsFactory() {

    }

    public static CurrencyConvertorFactory getCurrencyConvertorFactoryInstance() throws CannotInstantiateFactoryException {

        return getInstance().getCurrencyConvertor();

    }

    /**

     * Returns instance of CurrencyConvertorFactory 

     * @return new instance of CurrencyConvertorFactory

     * @throws CannotInstantiateFactoryException

     */

    private synchronized CurrencyConvertorFactory getCurrencyConvertor() throws CannotInstantiateFactoryException {

        if (currencyConvertorFactoryInstance == null) {//intern implementation

//            String className = System.getProperty("currencyFactory", CurrencyConvertorFactoryImpl.class.getName());

//            try {

//                currencyConvertorFactoryInstance = (CurrencyConvertorFactory) Class.forName(className).newInstance();

//            } catch (Exception e) {

//                throw new CannotInstantiateFactoryException(e);

//            }

            //without reflection

            currencyConvertorFactoryInstance = new CurrencyConvertorFactoryImpl();

        }

        return currencyConvertorFactoryInstance;

    }

    public static ConvertorsFactory getInstance() {

        return instance;

    }

}