Let's talk about threadlocalinsecurerandom

I took a look at random number correlation today , Accidentally found this class .

This looks really good , There is an inheritance SecurityRandom, And with ThreadLocal word , Does it have the characteristics of both , Become a combination ？

Let's explore how .

First, let's see how it generates random numbers

    @Override
    public int nextInt() {
    
        return random().nextInt();
    }

track , Looks like this random Method is its core .

    private static Random random() {
    
        return PlatformDependent.threadLocalRandom();
    }

PlatformDependent yes netty Under the , We'll talk about it later .

track

    public static Random threadLocalRandom() {
    
        return RANDOM_PROVIDER.current();
    }

track

private interface ThreadLocalRandomProvider {
    
    Random current();
}

track , Oh ～

It's here , It used to be on the bottom floor ThreadLocalRandom ah , Not out of date jdk7 And above , use jdk In this way .

    static {
    
        if (javaVersion() >= 7) {
    
            RANDOM_PROVIDER = new ThreadLocalRandomProvider() {
    
                @Override
                @SuppressJava6Requirement(reason = "Usage guarded by java version check")
                public Random current() {
    
                    return java.util.concurrent.ThreadLocalRandom.current();
                }
            };
        } else {
    
            RANDOM_PROVIDER = new ThreadLocalRandomProvider() {
    
                @Override
                public Random current() {
    
                    return ThreadLocalRandom.current();
                }
            };
        }

Take a look at netty and jdk Under the ThreadLocalRandom Realization way , There is still a big difference , If you are interested, go and have a look by yourself .

I have a look back ThreadLocalInsecureRandom Is not public Embellished , Nothing , Class is over .