public long nextLong()

in benchmarks/src/main/java/org/apache/omid/benchmarks/utils/ZipfianGenerator.java [221:264]
25 lines of code
7 McCabe index (conditional complexity)

    public long nextLong(long itemcount) {
        //from "Quickly Generating Billion-Record Synthetic Databases", Jim Gray et al, SIGMOD 1994

        if (itemcount != countforzeta) {

            //have to recompute zetan and eta, since they depend on itemcount
            synchronized (this) {
                if (itemcount > countforzeta) {
                    //System.err.println("WARNING: Incrementally recomputing Zipfian distribtion. (itemcount="+itemcount+" countforzeta="+countforzeta+")");

                    //we have added more items. can compute zetan incrementally, which is cheaper
                    zetan = zeta(countforzeta, itemcount, theta, zetan);
                    eta = (1 - Math.pow(2.0 / items, 1 - theta)) / (1 - zeta2theta / zetan);
                } else if ((itemcount < countforzeta) && (allowitemcountdecrease)) {
                    //have to start over with zetan
                    //note : for large itemsets, this is very slow. so don't do it!

                    //TODO: can also have a negative incremental computation, e.g. if you decrease the number of items, then just subtract
                    //the zeta sequence terms for the items that went away. This would be faster than recomputing from scratch when the number of items
                    //decreases

                    System.err.println("WARNING: Recomputing Zipfian distribtion. This is slow and should be avoided. (itemcount=" + itemcount + " countforzeta=" + countforzeta + ")");

                    zetan = zeta(itemcount, theta);
                    eta = (1 - Math.pow(2.0 / items, 1 - theta)) / (1 - zeta2theta / zetan);
                }
            }
        }

        double u = random.nextDouble();
        double uz = u * zetan;

        if (uz < 1.0) {
            return 0;
        }

        if (uz < 1.0 + Math.pow(0.5, theta)) {
            return 1;
        }

        long ret = base + (long) ((itemcount) * Math.pow(eta * u - eta + 1, alpha));
        setLastInt((int) ret);
        return ret;
    }