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This post is a continuation of my previous post about integration and unit testing practices. I encourage to read previous post first. Web Application Architecture Traditionally we were using MVC frameworks to implement our web applications. While this pattern worked great in a past it is not a case anymore. The problem is that our […]

Let’s continue our adventure with Akka and DDD (previous lesson). So far we have been concentrated on write/command side of the system. We have covered topics like command processing, event storage, sharding etc. but haven’t touched the other side of the system: the query side. Our goal of this lesson is to implement necessary infrastructure […]

When in June 2012 Red Hat finally released JBoss EAP 6 he marketed it as a high-performance, low-footprint and easy-to-manage cloud-centric solution. Solution that is able to decrease time-to-market for application delivery and reduce corresponding operational costs. Solution capable of bringing deployed applications into the cloud without the need to re-skill or diverge from open […]

Almost every ruby, Ruby on Rails project has some kind of a global configuration. Sometimes it’s a YAML file loaded 'as-is’, other times it’s a model or designated configuration class. There are cases when we have to fallback to default values. In a model or configuration class the easiest way is to use accessor with […]

Lately we are experiencing a holy war between TDD followers and those that stands against it. As a strong believer in OOP principles I should consider myself a TDD follower. However I think that the truth, as always, lies somewhere in between. I practice TDD only in a parts of an application, that I think […]

Recap of lesson 1 In previous lesson we have managed to implement abstraction of event sourced Aggregate Root (AR) using akka-persistence and use it to develop concrete AR class representing Reservation process. We have shown that AR is message driven component that reacts on command messages. If command (i.e ReserveProduct) is accepted AR produces event […]

In the recent post (Terminal Unleashed) I’ve introduced a great tool that makes terminal work easier and faster – tmux. I suggest you to read the previous post before further reading. Architecture & reminder Tmux is based on a client-server architecture – running tmux for the first time will start a server with one session […]

Web developers will, sooner or later, be forced to use a terminal. However not every programmer is aware that being proficient in using a console (and it’s tools) can speed up work A LOT. In this post I will show you the tool for handling multiple command lines with ease. tmux – sessions, windows tmux […]

Every developer has heard terms like loose or tight coupling yet still a lot have problems maintaining coupling in their codebase. Let’s take a look into some code and try to identify where it is tightly coupled and refactor making it more maintainable and testable. Facing a code So here is a class: A purpose […]

When comparing traditional and DDD/CQRS architectures (see my previous article) I said that the goal of DDD model is to decompose complex business domain into manageable pieces taking into account scalability and consistency requirements. What it means is that by bringing concepts like bounded contexts, transaction boundaries and event based communication DDD and CQRS are […]