C # implements Snowflake algorithm ID generation

http://blog.csdn.net/w200221626/article/details/52064976

C # implements Snowflake algorithm

    // <summary>    /// dynamic production of a regular ID    // </summary>     Public classSnowflake {Private Static LongMachineID;//Machine ID        Private Static LongDatacenterid = 0L;//Data ID        Private Static Longsequence = 0L;//counting starts from zero    Private Static LongTwepoch = 687888001020L;//Unique time random amount    Private Static LongMachineidbits = 5L;//Machine code bytes        Private Static LongDatacenteridbits = 5L;//bytes of data         Public Static LongMaxmachineid = -1l ^ -1l << (int) Machineidbits;//MAX Machine ID        Private Static LongMaxdatacenterid = -1l ^ ( -1l << (int) datacenteridbits);//MAX Data ID    Private Static LongSequencebits = 12L;//Counter bytes, 12 bytes to save the digital count    Private Static LongMachineidshift = sequencebits;//Machine code data left shift number, that is, the number of bits occupied by the back counter        Private Static LongDatacenteridshift = sequencebits + machineidbits;Private Static LongTimestampleftshift = sequencebits + machineidbits + datacenteridbits;//Timestamp left move bit is machine code + counter Total bytes + data byte number         Public Static LongSequencemask = -1l ^ -1l << (int) Sequencebits;//A microsecond can generate a count, if this value is reached until the next subtle in the generation    Private Static LongLasttimestamp = -1l;//Last time stamp        Private Static ObjectSyncRoot =New Object();//Locking Object        StaticSnowflake Snowflake; Public StaticSnowflake Instance () {if(Snowflake = =NULL) Snowflake =NewSnowflake ();returnSnowflake; } PublicSnowflake () {Snowflakes (0L,-1); } PublicSnowflake (LongMachineID) {Snowflakes (MachineID,-1); } PublicSnowflake (LongMachineID,LongDatacenterid) {Snowflakes (MachineID, Datacenterid); }Private voidSnowflakes (LongMachineID,LongDatacenterid) {if(MachineID >= 0) {if(MachineID > Maxmachineid) {Throw NewException ("Illegal machine code ID");            } Snowflake.machineid = MachineID; }if(Datacenterid >= 0) {if(Datacenterid > Maxdatacenterid) {Throw NewException ("Data center ID is illegal");            } Snowflake.datacenterid = Datacenterid; }        }// <summary>        // Generate current timestamp        // </summary>        // <returns> milliseconds </returns>        Private Static LongGettimestamp () {return(Long) (Datetime.utcnow-NewDateTime (1970, 1, 1, 0, 0, 0, DATETIMEKIND.UTC)).        TotalMilliseconds; }// <summary>        /// Get next microsecond timestamp        // </summary>        /// <param name= "Lasttimestamp" ></param>        // <returns></returns>        Private Static LongGetnexttimestamp (LongLasttimestamp) {Longtimestamp = Gettimestamp ();if(Timestamp <= Lasttimestamp)            {timestamp = Gettimestamp (); }returnTimestamp }// <summary>        /// Get ID of long shaping        // </summary>        // <returns></returns>         Public LongGetId () {Lock(SyncRoot) {Longtimestamp = Gettimestamp ();if(Snowflake.lasttimestamp = = timestamp) {//The same subtle generation IDSequence = (sequence + 1) & Sequencemask;//Use the & operation to calculate whether the count generated in that Microsecond has reached the upper limit                    if(sequence = = 0) {//A subtle inside generated ID count has reached the upper limit, waiting for the next subtletimestamp = Getnexttimestamp (Snowflake.lasttimestamp); }                }Else{//different microsecond generation IDsequence = 0L; }if(Timestamp < Lasttimestamp) {Throw NewException ("The timestamp is smaller than the last time the ID was generated, so the exception"); } Snowflake.lasttimestamp = timestamp;//Save the current timestamp as the timestamp of the last build ID                LongId = ((Timestamp-twepoch) << (int) timestampleftshift) | (Datacenterid << (int) datacenteridshift) | (MachineID << (int) machineidshift) | SequencereturnId; }        }

C # implements Snowflake algorithm ID generation