CronExpressionのgetFinalFireTime()を実現して、書くのがせっかちで、みんなは更に直します!

class MyCronExpr extends CronExpression
{
    /**
     *  ;
     * @return
     */
    public Date getFinalFireTime()
    {
        Calendar ret = Calendar.getInstance();
        Integer day = getMaxField(this.daysOfMonth, "Day");
        
        ret.set(Calendar.YEAR, getMaxField(this.years, "Year"));                    // 
        ret.set(Calendar.MONTH, getMaxField(this.months, "Month") - 1);             // 
        if (day != 0)
            ret.set(Calendar.DAY_OF_MONTH, getMaxField(this.daysOfMonth, "Day"));   // 
        else
            ret.set(Calendar.DAY_OF_WEEK, getMaxField(this.daysOfWeek, "Week"));    // 
        if (this.nthdayOfWeek != 0)
        {
            ret.set(Calendar.WEEK_OF_MONTH, this.nthdayOfWeek);
        }
        
        ret.set(Calendar.HOUR_OF_DAY, getMaxField(this.hours, "Hour"));              // 
        ret.set(Calendar.MINUTE, getMaxField(this.minutes, "Minute"));               // 
        ret.set(Calendar.SECOND, getMaxField(this.seconds, "Second"));               // 
        
        return ret.getTime();
    }

    public MyCronExpr(String expr) throws ParseException
    {
        super(expr);
    }
    
    private Integer getMaxField(TreeSet set, String field)
    {
        if (set == null)
        {
            return null;
        }
        
        Integer ret = 0;
        Integer temp = 0;
        Integer maxVal = 0;
        
        if ("Year".equalsIgnoreCase(field))
        {
            maxVal = 2099;
        }
        else if("Month".equalsIgnoreCase(field))
        {
            maxVal = 12;
        }
        else if("Week".equalsIgnoreCase(field))
        {
            maxVal = 7;
        }
        else if("Day".equalsIgnoreCase(field))
        {
            maxVal = 31;
        }
        else if("Hour".equalsIgnoreCase(field))
        {
            maxVal = 23;
        }
        else if("Minute".equalsIgnoreCase(field))
        {
            maxVal = 59;
        }
        else if("Second".equalsIgnoreCase(field))
        {
            maxVal = 59;
        }
        
        Iterator item = set.iterator();
        while (item.hasNext())
        {
            temp = (Integer)item.next();
            if (temp > ret && temp <= maxVal)
            {   // ;
                ret = temp;
            }
        }
        
        return ret;
    }
}