money.java

一个很好的开源项目管理系统源代码

package net.java.workeffort.infrastructure.uom;

import java.io.Serializable;
import java.math.BigDecimal;
import java.util.Currency;

/**
 * The money class. 
 * @author Antony Joseph
 */
public class Money implements Serializable {
    private static final int[] cents = new int[] { 1, 10, 100, 1000 };

    private long amount;
    private Currency currency;

    public Money(BigDecimal amount, Currency currency) {
        this.currency = currency;
        this.amount = Math.round(amount.doubleValue() * centFactor());
    }
    
    private Money(long amount, Currency currency) {
        this.currency = currency;
        this.amount = amount;
    }

    public BigDecimal getAmount() {
        return BigDecimal.valueOf(amount, currency.getDefaultFractionDigits());
    }

    public Currency getCurrency() {
        return currency;
    }

    public boolean equals(Object other) {
        return (other instanceof Money) && equals((Money) other);
    }

    public boolean equals(Money other) {
        return currency.equals(other.currency) && (amount == other.amount);
    }

    public int hashCode() {
        return (int) (amount ^ (amount >>> 32));
    }

    private int centFactor() {
        return cents[currency.getDefaultFractionDigits()];
    }

    public Money add(Money other) {
        assertSameCurrencyAs(other);
        return newMoney(amount + other.amount);
    }

    public Money subtract(Money other) {
        assertSameCurrencyAs(other);
        return newMoney(amount - other.amount);
    }

    public boolean greaterThan(Money other) {
        return (compareTo(other) > 0);
    }

    public boolean lessThan(Money other) {
        return (compareTo(other) < 0);
    }


    public Money multiply(BigDecimal amount) {
        return new Money(getAmount().multiply(amount), currency);
    }

    public int compareTo(Object other) {
        return compareTo((Money) other);
    }

    public int compareTo(Money other) {
        assertSameCurrencyAs(other);
        if (amount < other.amount)
            return -1;
        else if (amount == other.amount)
            return 0;
        else
            return 1;
    }

    public String toString() {
        return "amount=" + getAmount() + " currency=" + currency;  
    }

    private Money newMoney(long amount) {
        return new Money(amount, this.currency);
    }

    private void assertSameCurrencyAs(Money arg) {
        if (!currency.equals(arg.getCurrency()))
            throw new CurrencyMismatchException("Mismatch between currencies"
                    + currency + " and " + arg.getCurrency());
    }

}