Streams

A practical introduction to how Kafka distributes records across brokers and why partition planning matters.

In today’s data-driven world, the ability to process information in real-time is crucial.

Streams are convenient way to reduce the line of codes, but an understanding them is equally challenging. I write this blog, after realising a desperate attempt at solving a trivial problem just took overwhelming time. (Could be that I am getting old, but never late to learn things again)

Prime number is an age old problem. I am trying to solve it via streams. class PrimeCalculator { public int nth(int nth) { if (nth <= 0) throw new IllegalArgumentException(); // Will skip the nth - 1 // 2 to n-1 return IntStream.iterate(2, i -> i + 1).filter(PrimeCalculator::isPrime).skip(nth - 1).findFirst().getAsInt(); } public static boolean isPrime(int x) { // till half of x return IntStream.rangeClosed(2, (int) (x/2) ).dropWhile(i -> x % i != 0).findFirst().isEmpty(); } } Explanation # public int nth(int nth) { if (nth <= 0) throw new IllegalArgumentException(); // Will skip the nth - 1 // 2 to n-1 return IntStream.iterate(2, i -> i + 1).filter(PrimeCalculator::isPrime).skip(nth - 1).findFirst().getAsInt(); } The method nth(int) allows you to return the nth prime starting at 2, 3, 5....

Continuing from the last blog how about checking a pangram using streams. public class PangramChecker { private String allChars = "abcdefghijklmnopqrstuvwxyz"; public boolean isPangram(String input) { if (input.length() <= 0 || input.isBlank()){ return false; } return (allChars.chars().map(x -> (char) x).filter(x -> input.toLowerCase().indexOf(x) >= 0).count() == 26); } } All the for loops have been squeezed into a simple line

Stream is an new abstraction that lets one process data in a declarative way. A stream does not store data and, in that sense, is not a data structure. It also never modifies the underlying data source. The easiest way to learn a new API or a construct is by trying it. So here is an exercise that I tried to learn the Stream API. This is an exercise from exercism.io.