TraceAndSpanIdGenerator From nike.wingtips

TraceAndSpanIdGenerator.java

/**
 * Code from 
 *  https://github.com/Nike-Inc/wingtips/blob/38d8ce83207ffee3d638bf7466b8f7058bb36498/wingtips-core/src/main/java/com/nike/wingtips/TraceAndSpanIdGenerator.java#L60
 * Thanks to @adriancole
 */

public static long generate64BitRandomLong() {
    byte[] random8Bytes = new byte[8];
    random.nextBytes(random8Bytes);

    return convertBytesToLong(random8Bytes);
}

protected static long convertBytesToLong(byte[] byteArray) {
    if (byteArray.length != 8)
        throw new IllegalArgumentException("byteArray must be 8 bytes in length");

    long longVal = 0;
    for (int i=0; i<8; i++)
        longVal = (longVal << 8) | (byteArray[i] & 0xff);

    return longVal;
}

protected static Random getRandomInstance(String desiredSecureRandomImplementation) {
    Random randomToUse;

    try {
        randomToUse = SecureRandom.getInstance(desiredSecureRandomImplementation);
        randomToUse.setSeed(System.nanoTime());
    } catch (NoSuchAlgorithmException e) {
        logger.error("Unable to retrieve the {} SecureRandom instance. Defaulting to a new Random(System.nanoTime()) instead. NOTE: This means random longs will not cover " +
                "the full 64 bits of possible values! See the javadocs for Random.nextLong() for details. dtracer_error=true", desiredSecureRandomImplementation,  e);
        randomToUse = new Random(System.nanoTime());
    }

    return randomToUse;
}