package com.ezubo.global.util;

import org.apache.commons.lang3.time.DateFormatUtils;

import java.text.SimpleDateFormat;
import java.util.Date;

/**利用单例模式生成序列号 不适合分布式系统
 * Created by  on 2015-12-29.
 */
public class Generators {
    private static final String DATE_FORMAT = "yyyyMMddHHmmss";
    private static final SimpleDateFormat SIMPLE_DATE_FORMAT = new SimpleDateFormat(DATE_FORMAT);
    private static String forwardTime = "";
    private static Long no = 1l;
    private Generators(){
        super();
    }

    /**
     * 生成序列号
     * @param prefix
     * @return
     */
    public static  String getSeqNo(String prefix){
        synchronized (Generators.class){
            String pfix = prefix == null?"":prefix;
            String currentTime = SIMPLE_DATE_FORMAT.format(new Date());
            if(!currentTime.equals(forwardTime)){
                no = 1l;
            }
            String serializeNo = FormatUtil.leftpad(no++ , "00000000");
            forwardTime = currentTime;
            return pfix + currentTime + serializeNo;
        }
    }
}