com.livk.commons.util.Snowflake Maven / Gradle / Ivy
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/*
* Copyright 2021-2024 spring-boot-extension the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.livk.commons.util;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StringUtils;
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;
/**
*
* 雪花算法生成器
*
*
* @author livk
*/
@Slf4j
public final class Snowflake {
private final static long TIME_START_BASE = System.currentTimeMillis();
private final static long WORKER_ID_BITS = 5L;
private final static long DATACENTER_ID_BITS = 5L;
private final static long MAX_WORKER_ID = ~(-1L << WORKER_ID_BITS);
private final static long MAX_DATACENTER_ID = ~(-1L << DATACENTER_ID_BITS);
private final static long SEQUENCE_BITS = 12L;
private final static long WORKER_ID_SHIFT = SEQUENCE_BITS;
private final static long DATACENTER_ID_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS;
private final static long TIMESTAMP_LEFT_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS + DATACENTER_ID_BITS;
private final static long SEQUENCE_MASK = ~(-1L << SEQUENCE_BITS);
private static long lastTimestamp = -1L;
private final long workerId;
private final long datacenterId;
private long sequence = 0L;
/**
* 构建一个默认的生成器
*/
public Snowflake() {
this(-1, -1);
}
/**
* 构建一个的生成器
* @param workerId Working machine ID
* @param datacenterId Serial number
*/
public Snowflake(long workerId, long datacenterId) {
if (datacenterId > MAX_DATACENTER_ID || datacenterId < 0) {
datacenterId = getMaxDatacenterId();
}
if (workerId > MAX_WORKER_ID || workerId < 0) {
workerId = getMaxWorkerId(datacenterId);
}
this.workerId = workerId;
this.datacenterId = datacenterId;
}
/**
*
* 获取 maxWorkerId
*
* @param datacenterId the datacenter id
* @return the max worker id
*/
protected static long getMaxWorkerId(long datacenterId) {
StringBuilder buffer = new StringBuilder();
buffer.append(datacenterId);
String name = ManagementFactory.getRuntimeMXBean().getName();
if (StringUtils.hasText(name)) {
buffer.append(name.split("@")[0]);
}
return (buffer.toString().hashCode() & 0xffff) % (MAX_WORKER_ID + 1);
}
/**
*
* 数据标识id部分
*
* @return the max datacenter id
*/
protected static long getMaxDatacenterId() {
long id = 0L;
try {
InetAddress ip = InetAddress.getLocalHost();
NetworkInterface network = NetworkInterface.getByInetAddress(ip);
if (network == null) {
id = 1L;
}
else {
byte[] mac = network.getHardwareAddress();
id = ((0x000000FF & (long) mac[mac.length - 1])
| (0x0000FF00 & (((long) mac[mac.length - 2]) << 8))) >> 6;
id = id % (MAX_DATACENTER_ID + 1);
}
}
catch (Exception e) {
log.error("getDatacenterId:{}", e.getMessage(), e);
}
return id;
}
/**
* 获取下一个ID
* @return ID long
*/
public synchronized long nextId() {
long timestamp = System.currentTimeMillis();
if (timestamp < lastTimestamp) {
throw new IllegalArgumentException(String.format(
"Clock moved backwards. Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
}
if (lastTimestamp == timestamp) {
sequence = (sequence + 1) & SEQUENCE_MASK;
if (sequence == 0) {
timestamp = tilNextMillis(lastTimestamp);
}
}
else {
sequence = 0L;
}
lastTimestamp = timestamp;
return ((timestamp - TIME_START_BASE) << TIMESTAMP_LEFT_SHIFT) | (datacenterId << DATACENTER_ID_SHIFT)
| (workerId << WORKER_ID_SHIFT) | sequence;
}
private long tilNextMillis(long lastTimestamp) {
long timestamp = System.currentTimeMillis();
while (timestamp <= lastTimestamp) {
timestamp = System.currentTimeMillis();
}
return timestamp;
}
}