Business Logic Business Logic is the beating heart of every software system. Yet, many software developers need help identifying it. If we collectively want to build (and maintain!) programs that are easy to work with, we need to get good at this one task. …

Command and Queries Functions comprise the two complementary behaviours of Command Query Responsibility Separation or CQRS. While Query functions measure and report on the state of a system, Command functions, or Commands for short, change a system’s state. Command Functions How do Command Functions alter the state of a system? Simple, they…

When I first started programming, I fell in love — with the switch statement. Here I had found a way to construct long if ... elseif ... elseif ... else conditionals in a slightly more concise way. I was in programming heaven. The switch statement The switch statement exists in many programming languages…

The deeper we penetrate the realm of ‘The Code Smells’ — common symptoms afflicting predominantly older software systems — the worse the stench of putrefying software will get. However, smelly code is not always ancient — I also see programmers bake problems into greenfield projects. Last time we examined Software…

Sometimes the software we write seems to break for no specific reason. For example, a new bug appears in an area of our system that hasn’t been changed for a while. We may feel perplexed and frustrated by such program misbehaviour. Such problems are often signs of Software Fragility —…

What is the secret to good software architecture? What purpose does software serve? It allows developers to fashion bespoke systems that solve problems for its users. These ‘problems’ we call ‘business requirements’. To consider a software system successful, it must fulfil these requirements. This is WHAT a system does…

For a long time, I didn’t get interfaces. I am referring to interfaces as programming constructs in static languages like Java, C# and C++[1]. I thought it was weird to have interfaces in code. Why use an interface when I have the actual class? Why should I hide it behind…

In this article, we’ll take a look at the purpose of Object-Oriented Programming using an easy to understand example. We’ll model a simple line item in a sales order. To start with, let’s define the SalesOrderLine class as:

Want to blow the minds of your fellow developers with a powerful technique in software development that almost nobody is using? Then please read on. I am not exaggerating; in my 25 years in software development, I have seen almost no developer do this. I admit this could be an…