japod@34: package org.apidesign.apifest08.currency;
japod@34: 
japod@34: import java.io.Serializable;
japod@34: import java.util.Arrays;
japod@34: import java.util.Currency;
japod@34: 
japod@34: /**
japod@34:  * Convertor that is composed from other convertors. 
japod@34:  * @author lukas
japod@34:  *
japod@34:  */
japod@34: class CompositeConvertor implements ExtendedConvertor, Serializable {
japod@34: 
japod@34: 	private static final long serialVersionUID = -2702026568249130055L;
japod@34: 	
japod@34: 	private final ExtendedConvertor[] convertors;
japod@34: 
japod@34: 
japod@34: 	public CompositeConvertor(ExtendedConvertor... convertors) {
japod@34: 		this.convertors = convertors.clone();
japod@34: 		for (ExtendedConvertor convertor: this.convertors)
japod@34: 		{
japod@34: 			if (convertor==null)
japod@34: 			{
japod@34: 				throw new NullPointerException("One of the convertors to be merged is null");
japod@34: 			}
japod@34: 		}
japod@34: 	}
japod@34: 
japod@34: 	/**
japod@34: 	 * Returns true if the composite contains convertor that supports given conversion.
japod@34: 	 */
japod@34: 	public boolean isConversionSupported(Currency from, Currency to) {
japod@34: 		return findConvertorFor(from, to)!=null;
japod@34: 	}
japod@34: 
japod@34: 
japod@34: 	/**
japod@34: 	 * If the composite contains convertor that supports given conversion, delegates to its convert method.
japod@34: 	 * Throws {@link IllegalArgumentException} convertor supporting given conversion is not found. 
japod@34: 	 */
japod@34: 	public Money convert(Money amount, Currency destinationCurrency) throws IllegalArgumentException {
japod@34: 		ExtendedConvertor convertor = findConvertorFor(amount.getCurrency(), destinationCurrency);
japod@34: 		if (convertor!=null)
japod@34: 		{
japod@34: 			return convertor.convert(amount, destinationCurrency);
japod@34: 		}
japod@34: 		throw new IllegalArgumentException("Conversion not supported. Can not convert to "+destinationCurrency+".");
japod@34: 	}
japod@34: 	
japod@34: 	/**
japod@34: 	 * Finds convertor for given currencies. If not found, returns null. 
japod@34: 	 * @param from
japod@34: 	 * @param to
japod@34: 	 * @return
japod@34: 	 */
japod@34: 	ExtendedConvertor findConvertorFor(Currency from, Currency to) {
japod@34: 		//does linear search, in the future can cache the results.
japod@34: 		for (ExtendedConvertor convertor:convertors)
japod@34: 		{
japod@34: 			if (convertor.isConversionSupported(from, to))
japod@34: 			{
japod@34: 				return convertor;
japod@34: 			}
japod@34: 		}
japod@34: 		return null;
japod@34: 	}
japod@34: 	
japod@34: 
japod@34: 	@Override
japod@34: 	public String toString() {
japod@34: 		return getClass().getName()+" converts "+Arrays.toString(convertors);
japod@34: 	}
japod@34: 
japod@34: }