请问java生成任意位数的随机数

Question

我移植了樱花到Java中，它工作得很好。然而，我希望生成的不是 8 位数的数字，而是 12 位数的唯一数字。原来的 port 使用 16 位 machineId. 因为我们至少有2个数据中心，但不限于，我添加了8位的数据中心 - 使用IP地址的第二个八位组。我调整了所有比特长度的设置，无法生成12位数的数字。是否有受sonyflake的启发的算法？Twitters雪花生成独特的12位数字，它使用16位的 machineId 和8位 dataCenterId

注由于公司政策，我不能在这里发布我的原始Java移植。

EDIT: 这是我想出来的. 然而，它没有生成 12 位十进制数，而是生成了 10 或 11 位数字。我可以做哪些修改使它总是返回一个 12 位十进制数？我知道我需要修改 sequence 并重新计算时间。然而，我目前想专注于生成一个12位的十进制数。

public class Demo {

    /// 17 time + 4 dc + 10 machine + 8 sequence

    private static final int BIT_LEN_TIME = 17;
    private static final long BIT_WORKER_ID = 10L;
    private static final long BIT_LEN_DC = 4L;
    private static final long BIT_LEN_SEQUENCE = 8L;

    private static final int MAX_WORKER_ID = (int) (Math.pow(2, BIT_WORKER_ID) - 1);
    private static final long MAX_SEQUENCE = (int) (Math.pow(2, BIT_LEN_SEQUENCE) - 1);

    private static final double FLAKE_TIME_UNIT = 1e7; // nsec, i.e. 10 msec
    private static final double LEN_LIMIT = 1e11;
    private static final int START_SEQ = 0;

    private final ReentrantLock mutex = new ReentrantLock();

    private final Instant startInstant;
    private final long startTime;
    private final long dc;
    private long sequence;
    private long lastElapsedTime;
    private long worker;

    public Demo(Instant startInstant) {
        Objects.requireNonNull(startInstant, "startInstant cannot be null");
        if (startInstant.isBefore(Instant.EPOCH) || startInstant.isAfter(Instant.now())) {
            throw new EverestFlakeException("Base time should be after UNIX EPOCH, or before current time.");
        }

        this.startInstant = startInstant;
        this.startTime = this.toEverestFlakeTime(startInstant);
        this.sequence = START_SEQ;
        this.dc = this.msb(this.getDcId()); // 4 bits at most
        this.worker = this.workerId() & ((1 << BIT_WORKER_ID) - 1); // 10 bits at most
    }

    public long next() {
        long currentElapsedTime = this.currentElapsedTime(this.startTime);

        mutex.lock();
        long time = currentElapsedTime & ((1 << BIT_LEN_TIME) - 1); // 17 bits at most
        if (this.sequence == MAX_SEQUENCE) {
            this.sequence = START_SEQ;
            System.out.println("time = " + time);
            sleepMicro(currentElapsedTime - this.lastElapsedTime);
            time = this.currentElapsedTime(this.startTime) & ((1 << BIT_LEN_TIME) - 1);
            System.out.println("time = " + time);
        } else {
            // less than 15000
            if((currentElapsedTime - this.lastElapsedTime) < 0x3a98) {
                sleepMicro(currentElapsedTime - this.lastElapsedTime);
                time = this.currentElapsedTime(this.startTime) & ((1 << BIT_LEN_TIME) - 1);
            }
            this.sequence += (START_SEQ + 1) & MAX_SEQUENCE;
        }

        long id = (time << BIT_LEN_TIME) |
                (worker << BIT_WORKER_ID) |
                (dc << BIT_LEN_DC) |
                (sequence << BIT_LEN_SEQUENCE);
        id += LEN_LIMIT;
        this.lastElapsedTime = currentElapsedTime;
        mutex.unlock();

        return id;
    }

    private void sleepNano(long sleepTime) {
        try {
            System.out.println("nano sleeping for: " + sleepTime);
            TimeUnit.NANOSECONDS.sleep(sleepTime);
        } catch (Exception e) {
            //
        }
    }

    private void sleepMicro(long sleepTime) {
        try {
            System.out.println("micro sleeping for: " + sleepTime);
            TimeUnit.MICROSECONDS.sleep(sleepTime/100);
        } catch (Exception e) {
            //
        }
    }

    private long toEverestFlakeTime(Instant startInstant) {
        return unixNano(startInstant);
    }

    private long unixNano(Instant startInstant) {
        return NanoClock.systemUTC().nanos(startInstant);
    }

    private long currentElapsedTime(long startTime) {
        return this.toEverestFlakeTime(NanoClock.systemUTC().instant()) - startTime;
    }

    private long msb(long n) {
        n |= n >>> 1;
        n |= n >>> 2;
        n |= n >>> 4;
        n |= n >>> 8;
        n |= n >>> 16;
        n >>>= 1;
        n += 1;
        return n;
    }

    private int workerId() {
        return new SecureRandom().nextInt(MAX_WORKER_ID);
    }

    private int getDcId() {
        try {
            Socket socket = new Socket();
            socket.connect(new InetSocketAddress("google.com", 80));
            byte[] a = socket.getLocalAddress().getAddress();
            socket.close();
            return Byte.toUnsignedInt(a[1]);
        } catch (Exception e) {
            String message = "Failed to process machine id.";
            throw new EverestFlakeException(message, e);
        }
    }
}

请问java生成任意位数的随机数

12位数唯一分布式随机数发生器