japod@55: package org.apidesign.apifest08.currency;
japod@55: 
japod@55: 
japod@55: import java.math.BigDecimal;
japod@55: import java.util.Currency;
japod@55: 
japod@55: 
japod@55: /**
japod@55:  * The exchange rate between two currencies.
japod@55:  *
japod@55:  * @author D'Arcy Smith
japod@55:  * @version 1.0
japod@55:  */
japod@55: public final class ExchangeRate
japod@55: {
japod@55:     /**
japod@55:      * 
japod@55:      */
japod@55:     private final Currency currencyA;
japod@55: 
japod@55:     /**
japod@55:      * 
japod@55:      */
japod@55:     private final Currency currencyB;
japod@55: 
japod@55:     /**
japod@55:      * 
japod@55:      */
japod@55:     private final BigDecimal rateAtoB;
japod@55: 
japod@55:     /**
japod@55:      * 
japod@55:      */
japod@55:     private final BigDecimal rateBtoA;
japod@55: 
japod@55:     /**
japod@55:      * Construct an ExchangeRate with the specified values.
japod@55:      * 
japod@55:      * @param a the first currency
japod@55:      * @param b the second currency
japod@55:      * @param ra the rate to convert a to b
japod@55:      * @param rb the rate to covertt b to a
japod@55:      * @throws IllegalArgumentException if any parameter is null.
japod@55:      */
japod@55:     public ExchangeRate(final Currency   a,
japod@55:                         final Currency   b,
japod@55:                         final BigDecimal ra,
japod@55:                         final BigDecimal rb)
japod@55:     {
japod@55:         if(a == null)
japod@55:         {
japod@55:             throw new IllegalArgumentException("a cannot be null");
japod@55:         }
japod@55:         
japod@55:         if(b == null)
japod@55:         {
japod@55:             throw new IllegalArgumentException("b cannot be null");
japod@55:         }
japod@55:         
japod@55:         if(ra == null)
japod@55:         {
japod@55:             throw new IllegalArgumentException("ra cannot be null");
japod@55:         }
japod@55:         
japod@55:         if(rb == null)
japod@55:         {
japod@55:             throw new IllegalArgumentException("rb cannot be null");
japod@55:         }
japod@55:         
japod@55:         if(ra.compareTo(BigDecimal.ZERO) <= 0)
japod@55:         {
japod@55:             throw new IllegalArgumentException("ra cannot be <= 0, was: " + ra);
japod@55:         }
japod@55:         
japod@55:         if(rb.compareTo(BigDecimal.ZERO) <= 0)
japod@55:         {
japod@55:             throw new IllegalArgumentException("rb cannot be <= 0, was: " + ra);
japod@55:         }
japod@55:         
japod@55:         currencyA = a;
japod@55:         currencyB = b;
japod@55:         rateAtoB  = ra;
japod@55:         rateBtoA  = rb;
japod@55:     }
japod@55: 
japod@55:     /**
japod@55:      * Get the first currency.
japod@55:      * 
japod@55:      * @return the first currency.
japod@55:      */
japod@55:     public Currency getCurrencyA()
japod@55:     {
japod@55:         return currencyA;
japod@55:     }
japod@55: 
japod@55:     /**
japod@55:      * Get the second currency.
japod@55:      * 
japod@55:      * @return the second currency.
japod@55:      */
japod@55:     public Currency getCurrencyB()
japod@55:     {
japod@55:         return currencyB;
japod@55:     }
japod@55: 
japod@55:     /**
japod@55:      * Get the conversion rate from currencyA to currencyB.
japod@55:      * 
japod@55:      * @return the conversion rate from currencyA to currencyB.
japod@55:      */
japod@55:     public BigDecimal getRateAtoB()
japod@55:     {
japod@55:         return rateAtoB;
japod@55:     }
japod@55: 
japod@55:     /**
japod@55:      * Get the conversion rate from currencyB to currencyA.
japod@55:      * 
japod@55:      * @return the conversion rate from currencyB to currencyA.
japod@55:      */
japod@55:     public BigDecimal getRateBtoA()
japod@55:     {
japod@55:         return rateBtoA;
japod@55:     }
japod@55: }