package com.pfq.deal.risk.util;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashSet;
import java.util.List;
import java.util.Random;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 生成30位唯一數: yyyyMMddHHmmssSSS+伺服器IP後5位+3位遞增序號+5位隨機數
 * 如果將系統部署到叢集上面，情況有會有不同了，不同的伺服器叢集生成的這個數字，是有重合的概率的，
 * 因此，一般情況是，將叢集中的每個機器進行IP編碼，然後將機器編碼放在這個標識中以示區分
 * 
 * @author Dabria_ly 2017年8月24日
 */
public class Uidutil {
private static final Logger LOG = LoggerFactory.getLogger(Uidutil.class);
private static String no = "0";
private static String dateValue = "";//預設精確到毫秒的比對時間
private static Random rand = new Random();


public static synchronized String next() throws UnknownHostException {
String ipStr = InetAddress.getLocalHost().getHostAddress();// 獲取本機IP
ipStr = ipStr.substring(ipStr.indexOf("." + 2)).replace(".", "");
if(ipStr.length() > 5){
ipStr = ipStr.substring(0, 5);
}
String dateStr = new SimpleDateFormat("yyyyMMddHHmmssSSS").format(new Date());
String num = new StringBuilder().append(dateStr)
                        .append(ipStr).toString();
if (!(String.valueOf(dateStr)).equals(dateValue)) {//不是同一個時段，從0開始遞增序號
no = "0";
dateValue = dateStr;
}
num += getNo(no, num);
return num;
}


/**
 * 返回當前序號+1
 */
public static String getNo(String noCount, String num) {
long i = Long.parseLong(noCount);
i += 1;
noCount = "" + i;
for (int j = noCount.length(); j < 25 - num.length(); j++) {
noCount = "0" + noCount;
}
no = noCount;
return noCount;
}


/**
 * 利用Set中不允許有重複的元素的特性，來判斷集合元素中是否有重複元素
 * 
 * @param list:被判斷的集合
 * @return false:有重複元素或list為null; true:沒有重複元素
 */
private static boolean hasSame(List<? extends Object> list) {
if (null == list)
return false;
return list.size() == new HashSet<Object>(list).size();
}

/**
 * next()+5位隨機數
 * @return
 * @throws UnknownHostException
 */
public static String getTransactionId() throws UnknownHostException{
return new StringBuilder().append(next())
.append(String.valueOf(rand.nextInt(99999 - 10000 + 1) + 10000)).toString();
}


public static void main(String[] args) {
final List<String> guidList = new ArrayList<String>();
for (int i = 0; i < 10; i++) {// 開啟10個執行緒
new Thread(new Runnable() {
@Override
public void run() {
for (int j = 0; j < 10000; j++) {// 每個執行緒迴圈1w條資料
try {
String guid = getTransactionId();
System.out.println("guid="+guid+",length="+guid.length());
guidList.add(guid);
} catch (UnknownHostException e) {
LOG.error("未知主機IP錯誤-->【{}】", e);
}
}


}


}).start();
}


try {
Thread.sleep(30000);// sleep 30秒
LOG.info("集合個數-->【{}】", guidList.size());
LOG.info("沒有重複元素-->【{}】", hasSame(guidList));
} catch (InterruptedException e) {
LOG.error("sleep error-->【{}】", e);
}
}
}