Stream[Article]: 2018

Paxos protocol simulation in Akka

I have recently started implementing different distributed system protocols to get some understanding how they work. I think that using Akka Actors to simulate hosts is a good choice because they are easy to set up. What is more you can kill actors on demand to test some failure scenarios.

First protocol I implemented is Paxos - probably the most important consensus protocol, which guarantees storng consistecy, full transactions, read/write failover and prevents from data loss. This comes with the cost of higher latency and lower throughput. In terms of CAP theorem, Paxos is used to make your system CP. I used this sweet article as a reference.

Implementation can be found on my github repository. Go to the Test.scala and run some simulations.

Feb

Don't sleep when you test!

When I started working as a Java Developer, me and my teammate got a first task to repair all broken tests (great task for new starters!) in some old project. Replacing some old configuration and upgrading a few libraries helped making the tests status green but there was another problem. End-to-end test suite took a few hours to pass making it impossible to get the feedback for a new change quickly.

Feb

5 Less Known Cool Intellij Features

In this article I am going to share some cool features I stumbled upon while coding with Intellij. These are not the most popular/productivity improving ones - for these you should watch this video.

1. Set debugger breakpoint by pattern

Problem: You want to check if the debugger steps into some code during the run. Usually you suspect where the flow will end up but sometimes finding the exact line could be hard.

Feb

Simple Map Reduce concept implementation

I have recently pushed very simple Map Reduce concept implementation on my Github account (click). My idea was to focus on the concept and mock the rest.

Jan

Kotlin null safety for Optional experienced

In this article I will try to map methods of Java’s Optional to Kotlin’ssimilar scattered language features and built-in functions. The code in the examples is written in Kotlin, because the language has all the JDK classes available.

Representation

Let’s start with the representation.

Jan

Understanding flatMap

Have you ever scrolled someone’s code and bumped into this weird method called flatMap, not knowing what it actually does from the context? Or maybe you compared it with method map but didn’t really see much difference? If that is the case then this article is for you.

flatMap is extremly usfull when you try to do proper functional programming. In Java it usually means using Streams and Optionals - concepts introduced in version 8.