japod@6: package org.apidesign.apifest08.currency;
japod@6: 
japod@6: import java.io.Serializable;
japod@6: import java.math.BigDecimal;
japod@6: import java.math.RoundingMode;
japod@6: import java.util.Currency;
japod@6: 
japod@6: /**
japod@6:  * Default {@link Convertor} implementation. Exchange rate is stored as equivalents. It means if we have USD to CZK convertor and USD1 = CZK17 
japod@6:  * we store 1 in sourceEquivalent and 17 in destinationEquivalent. This class is immutable.
japod@6:  * @author lukas
japod@6:  *
japod@6:  */
japod@34: class DefaultConvertor implements ExtendedConvertor, Serializable {
japod@6: 
japod@34: 	private static final long serialVersionUID = 6660014633685135034L;
japod@6: 
japod@6: 	/**
japod@6: 	 * Equivalent in source currency.
japod@6: 	 */
japod@6: 	private final BigDecimal sourceEquivalent;
japod@6: 	
japod@6: 	/**
japod@6: 	 * Equivalent in destination currency.
japod@6: 	 */
japod@6: 	private final BigDecimal destinationEquivalent;
japod@6: 	
japod@6: 	private final Currency sourceCurrency;
japod@6: 	
japod@6: 	private final Currency destinationCurrency;
japod@6: 	
japod@34: 	public DefaultConvertor(Money sourceEquivalent, Money destinationEquivalent) {
japod@6: 		super();
japod@34: 		if (BigDecimal.ZERO.compareTo(sourceEquivalent.getAmount())==0)
japod@16: 		{
japod@16: 			throw new IllegalArgumentException("Source equivalent amount can not be 0.");
japod@16: 		}
japod@34: 		if (BigDecimal.ZERO.compareTo(destinationEquivalent.getAmount())==0)
japod@16: 		{
japod@16: 			throw new IllegalArgumentException("Destination equivalent amount can not be 0.");
japod@16: 		}
japod@34: 		this.sourceEquivalent = sourceEquivalent.getAmount();
japod@34: 		this.destinationEquivalent = destinationEquivalent.getAmount();
japod@34: 		this.sourceCurrency = sourceEquivalent.getCurrency();
japod@34: 		this.destinationCurrency = destinationEquivalent.getCurrency();
japod@6: 	}
japod@6: 	
japod@16: 	public Money convert(Money amount, Currency destinationCurrency) {
japod@16: 		if (amount==null)
japod@6: 		{
japod@6: 			throw new NullPointerException("Money is null");
japod@6: 		}
japod@16: 		if (destinationCurrency==null)
japod@6: 		{
japod@16: 			throw new NullPointerException("destionationCurrency is null");
japod@6: 		}
japod@16: 		if (!amount.getCurrency().equals(getSourceCurrency()))
japod@16: 		{
japod@16: 			throw new IllegalArgumentException("Can not convert from "+amount.getCurrency()+". Converts between "+getSourceCurrency()+" and "+getDestinationCurrency());
japod@16: 		}
japod@16: 		if (!getDestinationCurrency().equals(destinationCurrency))
japod@16: 		{
japod@16: 			throw new IllegalArgumentException("Can not convert to "+destinationCurrency+". Converts between "+getSourceCurrency()+" and "+getDestinationCurrency());
japod@16: 		}
japod@16: 		BigDecimal sourceAmount = amount.getAmount();
japod@16: 		BigDecimal destinationAmount = sourceAmount.multiply(destinationEquivalent).divide(sourceEquivalent, 2, RoundingMode.HALF_UP);
japod@6: 		return new MoneyImpl(destinationAmount, getDestinationCurrency());
japod@6: 	}
japod@34: 	
japod@34: 	public boolean isConversionSupported(Currency from, Currency to) {
japod@34: 		return sourceCurrency.equals(from) && destinationCurrency.equals(to);
japod@6: 	}
japod@6: 
japod@6: 	public BigDecimal getSourceEquivalent() {
japod@6: 		return sourceEquivalent;
japod@6: 	}
japod@6: 
japod@6: 	public BigDecimal getDestinationEquivalent() {
japod@6: 		return destinationEquivalent;
japod@6: 	}
japod@6: 
japod@6: 	public Currency getSourceCurrency() {
japod@6: 		return sourceCurrency;
japod@6: 	}
japod@6: 
japod@6: 	public Currency getDestinationCurrency() {
japod@6: 		return destinationCurrency;
japod@6: 	}
japod@6: 	
japod@6: 	@Override
japod@6: 	public String toString() {
japod@6: 		return getClass().getName()+" converts "+getSourceCurrency()+" to "+getDestinationCurrency()+" "
japod@6: 			+getSourceCurrency()+getSourceEquivalent()+"="+getDestinationCurrency()+getDestinationEquivalent();
japod@6: 	}
japod@6: }