/*
 *  DateUtils.java
 *  
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Library General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *  
 *  Author: Winter Lau (javayou@gmail.com)
 *  http://dlog4j.sourceforge.net
 */
package com.liusoft.dlog4j.util;

import java.sql.Time;
import java.util.Calendar;
import java.util.Date;

/**
 * 日期相關的工具類
 * @author Winter Lau
 */
public class DateUtils extends org.apache.commons.lang.time.DateUtils{

	/**
	 * 合并日期和時間
	 * @param date
	 * @param time
	 * @return
	 */
	public static Calendar mergeDateTime(Date date, Time time){
		Calendar cal = Calendar.getInstance();
		if(date!=null)
			cal.setTime(date);
		if(time!=null){
			Calendar temp = Calendar.getInstance();
			temp.setTime(time);
			cal.set(Calendar.HOUR_OF_DAY, temp.get(Calendar.HOUR_OF_DAY));
			cal.set(Calendar.MINUTE, temp.get(Calendar.MINUTE));
			cal.set(Calendar.SECOND, temp.get(Calendar.SECOND));
			cal.set(Calendar.MILLISECOND, temp.get(Calendar.MILLISECOND));
		}
		return cal;
	}
	
	/**
	 * 返回兩個日期相差的天數
	 * @param d1
	 * @param d2
	 * @return
	 */
	public static int diff_in_date(Date d1, Date d2){
		return (int)(d1.getTime() - d2.getTime())/86400000;
	}

	/**
	 * 獲取某天開始的那一刻
	 * @param year
	 * @param month
	 * @param date
	 * @return
	 */
	public static Calendar getDateBegin(int year, int month, int date){
		Calendar begin_time = Calendar.getInstance();
		begin_time.set(Calendar.YEAR, year);
		begin_time.set(Calendar.MONTH, month-1);
		begin_time.set(Calendar.DATE, date);
		begin_time.set(Calendar.HOUR_OF_DAY, 0);
		begin_time.set(Calendar.MINUTE, 0);
		begin_time.set(Calendar.SECOND, 0);
		begin_time.set(Calendar.MILLISECOND, 0);
		return begin_time;
	}
	
	/**
	 * 清除日歷的時間字段
	 * @param cal
	 */
	public static void resetTime(Calendar cal){
		cal.set(Calendar.HOUR_OF_DAY,0);
		cal.set(Calendar.MINUTE,0);
		cal.set(Calendar.SECOND,0);
		cal.set(Calendar.MILLISECOND,0);
	}
	
}