package org.apidesign.apifest08.currency;

 import java.math.BigDecimal;

 import java.util.Currency;

 /**

  * An amount of a currency.

  * Immutable.

  * @author jdvorak

  */

 public class MonetaryAmount {

     private final BigDecimal amount;

     private final Currency currency;

     /**

      * A new amount.

      * @param amount the quantity of the currency; must not be null

      * @param currency the currency; must not be null

      */

     public MonetaryAmount( final BigDecimal amount, final Currency currency ) {

         this.amount = amount;

         this.currency = currency;

         if ( amount == null ) {

             throw new NullPointerException( "The amount" );

         }

         if ( currency == null ) {

             throw new NullPointerException( "The currency" );

         }

     }

     /**

      * A new amount.

      * @param amount the quantity of the currency; must not be null

      * @param currency the currency; must not be null

      */

     public MonetaryAmount( final double amount, final Currency currency ) {

         this( new BigDecimal( amount ), currency );

     }

     /**

      * The amount.

      * @return the amount

      */

     public BigDecimal getAmount() {

         return amount;

     }

     /**

      * The currency.

      * @return the currency

      */

     public Currency getCurrency() {

         return currency;

     }

     /**

      * The string representation of the monetary amount.

      * @return the amount, a non-breakable space, the currency

      */

     @Override

     public String toString() {

         return amount.toPlainString() + "\u00a0" + currency.toString();

     }

     /**

      * Two monetary amounts are equal to each other iff they have equal amounts of equal currencies.

      * @param other the other object

      * @return equality

      */

     @Override

     public boolean equals( final Object other ) {

         if ( other instanceof MonetaryAmount ) {

             final MonetaryAmount otherMonetaryAmount = (MonetaryAmount) other;

             return getAmount().equals( otherMonetaryAmount.getAmount() ) && getCurrency().equals( otherMonetaryAmount.getCurrency() );

         }

         return false;

     }

     /**

      * The hash code combines the hash codes of the amount and of the currency.

      * @return hash code

      */

     @Override

     public int hashCode() {

         return amount.hashCode() * 37 + currency.hashCode();

     }

 }