public synchronized long nextId() {
        long currentStamp = getTimeMill();
        if (currentStamp < lastStamp) {
            throw new RuntimeException("Clock moved backwards.");
        }

        if (currentStamp == lastStamp) {
            sequence = (sequence + 1) & this.maxSequenceValue;
            if (sequence == 0L) {
                lastStamp = tilNextMillis();
            }
        } else {
            sequence = 0L;
        }

        lastStamp = currentStamp;

        return (currentStamp - START_STAMP) <<
                timestampBitLeftOffset | idcId << idcBitLeftOffset | machineId << machineBitLeftOffset | sequence;
    }
public synchronized long nextId() {
        long currentStamp = getTimeMill();
        if (currentStamp < lastStamp) {
            throw new RuntimeException("Clock moved backwards.");
        }

        if (currentStamp == lastStamp) {
            sequence = (sequence + 1) & this.maxSequenceValue;
            if (sequence == 0L) {
                lastStamp = tilNextMillis();
            }
        } else {
            sequence = 0L;
        }

        lastStamp = currentStamp;

        return (currentStamp - START_STAMP) <<
                timestampBitLeftOffset | idcId << idcBitLeftOffset | machineId << machineBitLeftOffset | sequence;
    }
public synchronized long nextId ( ) { long currentStamp = getTimeMill ( ) ; if ( currentStamp < lastStamp ) { throw new RuntimeException ( "Clock moved backwards." ) ; } if ( currentStamp == lastStamp ) { sequence = ( sequence + 1 ) & this . maxSequenceValue ; if ( sequence == 0L ) { lastStamp = tilNextMillis ( ) ; } } else { sequence = 0L ; } lastStamp = currentStamp ; return ( currentStamp - START_STAMP ) << timestampBitLeftOffset | idcId << idcBitLeftOffset | machineId << machineBitLeftOffset | sequence ; }
产生下一个ID
@return id
产生下一个ID