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+package org.maxkey.util;
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+
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+import java.util.Calendar;
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+import java.util.Date;
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+
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+/**
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+ * 描述: Twitter的分布式自增ID雪花算法snowflake (Java版)
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+ *
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+ * @author Crystal.Sea
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+ * @create 2021-04-17
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+ **/
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+public class SnowFlakeId {
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+
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+ /**
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+ * 起始的时间戳
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+ */
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+ private final static long START_STMP = 1480166465631L;
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+
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+ /**
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+ * 每一部分占用的位数
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+ */
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+ private final static long SEQUENCE_BIT = 12; //序列号占用的位数
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+ private final static long MACHINE_BIT = 5; //机器标识占用的位数
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+ private final static long DATACENTER_BIT = 5;//数据中心占用的位数
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+
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+ /**
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+ * 每一部分的最大值
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+ */
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+ private final static long MAX_DATACENTER_NUM = -1L ^ (-1L << DATACENTER_BIT);
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+ private final static long MAX_MACHINE_NUM = -1L ^ (-1L << MACHINE_BIT);
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+ private final static long MAX_SEQUENCE = -1L ^ (-1L << SEQUENCE_BIT);
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+
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+ /**
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+ * 每一部分向左的位移
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+ */
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+ private final static long MACHINE_LEFT = SEQUENCE_BIT;
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+ private final static long DATACENTER_LEFT = SEQUENCE_BIT + MACHINE_BIT;
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+ private final static long TIMESTMP_LEFT = DATACENTER_LEFT + DATACENTER_BIT;
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+
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+ private long datacenterId; //数据中心
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+ private long machineId; //机器标识
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+ private long sequence = 0L; //序列号
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+ private long lastStmp = -1L;//上一次时间戳
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+ private String dateTime;
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+
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+ public SnowFlakeId(long datacenterId, long machineId) {
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+ if (datacenterId > MAX_DATACENTER_NUM || datacenterId < 0) {
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+ throw new IllegalArgumentException("datacenterId can't be greater than MAX_DATACENTER_NUM or less than 0");
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+ }
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+ if (machineId > MAX_MACHINE_NUM || machineId < 0) {
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+ throw new IllegalArgumentException("machineId can't be greater than MAX_MACHINE_NUM or less than 0");
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+ }
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+ this.datacenterId = datacenterId;
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+ this.machineId = machineId;
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+ }
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+
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+ public SnowFlakeId(long datacenterId, long machineId, long sequence, long lastStmp) {
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+ super();
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+ this.datacenterId = datacenterId;
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+ this.machineId = machineId;
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+ this.sequence = sequence;
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+ this.lastStmp = lastStmp;
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+ dateTime =DateUtils.toUtc( fromatTime(lastStmp));
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+ }
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+
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+ /**
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+ * 产生下一个ID
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+ *
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+ * @return
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+ */
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+ public synchronized long nextId() {
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+ long currStmp = getNewstmp();
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+ if (currStmp < lastStmp) {
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+ throw new RuntimeException("Clock moved backwards. Refusing to generate id");
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+ }
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+
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+ if (currStmp == lastStmp) {
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+ //相同毫秒内,序列号自增
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+ sequence = (sequence + 1) & MAX_SEQUENCE;
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+ //同一毫秒的序列数已经达到最大
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+ if (sequence == 0L) {
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+ currStmp = getNextMill();
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+ }
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+ } else {
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+ //不同毫秒内,序列号置为0
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+ sequence = 0L;
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+ }
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+
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+ lastStmp = currStmp;
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+
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+ return (currStmp - START_STMP) << TIMESTMP_LEFT //时间戳部分
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+ | datacenterId << DATACENTER_LEFT //数据中心部分
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+ | machineId << MACHINE_LEFT //机器标识部分
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+ | sequence; //序列号部分
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+ }
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+
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+ private long getNextMill() {
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+ long mill = getNewstmp();
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+ while (mill <= lastStmp) {
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+ mill = getNewstmp();
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+ }
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+ return mill;
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+ }
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+
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+ private long getNewstmp() {
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+ return System.currentTimeMillis();
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+ }
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+
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+ public SnowFlakeId parse(long id) {
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+ String sonwFlakeId = Long.toBinaryString(id);
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+ System.out.println(sonwFlakeId);
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+ int len = sonwFlakeId.length();
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+ int sequenceStart = (int) (len < MACHINE_LEFT ? 0 : len - MACHINE_LEFT);
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+ int workerStart = (int) (len < DATACENTER_LEFT ? 0 : len - DATACENTER_LEFT);
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+ int timeStart = (int) (len < TIMESTMP_LEFT ? 0 : len - TIMESTMP_LEFT);
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+ String sequence = sonwFlakeId.substring(sequenceStart, len);
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+ String workerId = sequenceStart == 0 ? "0" : sonwFlakeId.substring(workerStart, sequenceStart);
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+ String dataCenterId = workerStart == 0 ? "0" : sonwFlakeId.substring(timeStart, workerStart);
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+ String time = timeStart == 0 ? "0" : sonwFlakeId.substring(0, timeStart);
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+ int sequenceInt = Integer.valueOf(sequence, 2);
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+ int workerIdInt = Integer.valueOf(workerId, 2);
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+ int dataCenterIdInt = Integer.valueOf(dataCenterId, 2);
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+ long diffTime = Long.parseLong(time, 2);
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+ long timeLong = diffTime + START_STMP;
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+
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+ SnowFlakeId snowFlakeIdParse =new SnowFlakeId(dataCenterIdInt,workerIdInt,sequenceInt,timeLong);
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+
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+ return snowFlakeIdParse;
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+ }
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+
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+ private static Date fromatTime(long date) {
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+ Calendar calendar = Calendar.getInstance();
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+ calendar.setTimeInMillis(date);
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+ return calendar.getTime();
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+ }
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+
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+
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+
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+ public long getDatacenterId() {
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+ return datacenterId;
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+ }
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+
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+ public void setDatacenterId(long datacenterId) {
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+ this.datacenterId = datacenterId;
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+ }
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+
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+ public long getMachineId() {
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+ return machineId;
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+ }
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+
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+ public void setMachineId(long machineId) {
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+ this.machineId = machineId;
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+ }
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+
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+ public long getSequence() {
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+ return sequence;
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+ }
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+
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+ public void setSequence(long sequence) {
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+ this.sequence = sequence;
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+ }
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+
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+ public long getLastStmp() {
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+ return lastStmp;
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+ }
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+
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+ public void setLastStmp(long lastStmp) {
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+ this.lastStmp = lastStmp;
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+ }
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+
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+ public String getDateTime() {
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+ return dateTime;
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+ }
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+
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+ public void setDateTime(String dateTime) {
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+ this.dateTime = dateTime;
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+ }
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+
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+ public static void main(String[] args) {
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+ SnowFlakeId snowFlake = new SnowFlakeId(20, 30);
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+
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+ long start = System.currentTimeMillis();
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+ for (int i = 0; i < 1000000; i++) {
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+ System.out.println(snowFlake.nextId());
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+ }
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+
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+ System.out.println(System.currentTimeMillis() - start);
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+
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+
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+ }
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+}
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