com.baidu.fsg.uid

类 BitsAllocator

java.lang.Object

com.baidu.fsg.uid.BitsAllocator

public class BitsAllocator
extends Object

对SnowFlake 的ID进行位操作的共聚类

为UID分配64位(long)
sign (fixed 1bit) -> deltaSecond -> workerId -> sequence(within the same second)

作者:

yutianbao

字段概要

字段

限定符和类型	字段和说明
static int	TOTAL_BITS Total 64 bits

构造器概要

构造器

构造器和说明
BitsAllocator(int timestampBits, int workerIdBits, int sequenceBits) Constructor with timestampBits, workerIdBits, sequenceBits The highest bit used for sign, so 63 bits for timestampBits, workerIdBits, sequenceBits

方法概要

限定符和类型	方法和说明
long	allocate(long deltaSeconds, long workerId, long sequence) 这里就是把不同的字段放到相应的位上 id的总体结构是： sign (fixed 1bit) -> deltaSecond -> workerId -> sequence(within the same second) deltaSecond 左移（workerIdBits + sequenceBits）位，workerId左移sequenceBits位，此时就完成了字节的分配 Allocate bits for UID according to delta seconds & workerId & sequence Note that: The highest bit will always be 0 for sign
long	getMaxDeltaSeconds()
long	getMaxSequence()
long	getMaxWorkerId()
int	getSequenceBits()
int	getSignBits() Getters
int	getTimestampBits()
int	getTimestampShift()
int	getWorkerIdBits()
int	getWorkerIdShift()
String	toString()

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

字段详细资料

TOTAL_BITS

public static final int TOTAL_BITS

Total 64 bits

另请参阅:

常量字段值

构造器详细资料

BitsAllocator

public BitsAllocator(int timestampBits,
                     int workerIdBits,
                     int sequenceBits)

Constructor with timestampBits, workerIdBits, sequenceBits
The highest bit used for sign, so 63 bits for timestampBits, workerIdBits, sequenceBits

方法详细资料

allocate

public long allocate(long deltaSeconds,
                     long workerId,
                     long sequence)

这里就是把不同的字段放到相应的位上 id的总体结构是： sign (fixed 1bit) -> deltaSecond -> workerId -> sequence(within the same second) deltaSecond 左移（workerIdBits + sequenceBits）位，workerId左移sequenceBits位，此时就完成了字节的分配

Allocate bits for UID according to delta seconds & workerId & sequence
Note that: The highest bit will always be 0 for sign

参数:

deltaSeconds -

workerId -

sequence -

返回:

getSignBits

public int getSignBits()

Getters

getTimestampBits

public int getTimestampBits()

getWorkerIdBits

public int getWorkerIdBits()

getSequenceBits

public int getSequenceBits()

getMaxDeltaSeconds

public long getMaxDeltaSeconds()

getMaxWorkerId

public long getMaxWorkerId()

getMaxSequence

public long getMaxSequence()

getTimestampShift

public int getTimestampShift()

getWorkerIdShift

public int getWorkerIdShift()

toString

public String toString()

覆盖:

toString 在类中 Object