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);

    }

}