package org.apidesign.apifest08.currency;

 import java.io.Serializable;

 /**

  * Value class, holding an amount of the currency & an identifier of the currency.

  * Designed to be an immutable.

  * 

  * Because of a vague definition of types of the both fields,

  * the class has generic types, used as types of the fields.

  * These types should be immutable classes, too.

  * 

  * @author ked

  */

 public final class CurrencyValue<AmountType, IdentifierType> implements Serializable {

     private final AmountType amount;

     private final IdentifierType identifier;

     private CurrencyValue(AmountType amount, IdentifierType identifier) {

         this.amount = amount;

         this.identifier = identifier;

     }

     public AmountType getAmount() {

         return amount;

     }

     public IdentifierType getIdentifier() {

         return identifier;

     }

     @Override

     public boolean equals(Object obj) {

         if (obj == null) {

             return false;

         }

         if (getClass() != obj.getClass()) {

             return false;

         }

         final CurrencyValue other = (CurrencyValue) obj;

         if (this.amount != other.amount && (this.amount == null || !this.amount.equals(other.amount))) {

             return false;

         }

         if (this.identifier != other.identifier && (this.identifier == null || !this.identifier.equals(other.identifier))) {

             return false;

         }

         return true;

     }

     @Override

     public int hashCode() {

         int hash = 7;

         hash = 97 * hash + (this.amount != null ? this.amount.hashCode() : 0);

         hash = 97 * hash + (this.identifier != null ? this.identifier.hashCode() : 0);

         return hash;

     }

     /**

      * Creates new instance.

      * Generic types of the new instance are derived from types of the parameters.

      * 

      * @param <AmountType> type of the currency amount

      * @param <IdentifierType> type of the currency identifier

      * @param amount currency amount

      * @param identifier currency identifier

      * @return new instance

      */

     public static <AmountType, IdentifierType> CurrencyValue<AmountType, IdentifierType> getCurrencyValue(AmountType amount, IdentifierType identifier) {

         return new CurrencyValue<AmountType, IdentifierType>(amount, identifier);

     }

 }