Ron Jeffries has said "code never lies, comments sometimes do". What makes comments sometimes lie? Usually the reason is that we don't keep them up to date. In this blog post I have written about few commenting anti-patterns and how to avoid lying comments.
"Make it a practice to present and discuss each implementation at one-third completion", wrote Adam Tornhill in his excellent Software Desing X-Rays book. Since reading that book I've been thinking about it, and I wrote why I strongly agree with it. Practically it improves code quality (which I value really high).
I wanted to recap this series about SOLID principles. In my opinion SOLID can be summarized with two things: "Code against interfaces, not implementations" and "write small classes/interfaces". If we follow those two things, our code would be close to SOLID.
"Program to an interface, not an implementation" is a famous quote by Gang of Four. Even if it is not the definition of the dependency inversion principle, it is really close to it. Another related quote is by Robert C. Martin: "depend on abstractions, not on concretions". While writing this blog post I concretely learned what these quotes practically mean.
Interface segregation principle (ISP) says that clients should not be forced to depend upon interfaces that they do not use. Practically that means that we should have rather small interfaces with just few (or even one) methods than fat interfaces with many methods. In this blog post I will explain what ISP is and what relationship it has with Liskov substitution and single responsibility principles.
You can't get any idea of what Liskov substitution principle (LSP) is from its name. And its definition is hard to understand. But when you dig into it you'll find that it is quite important and not that difficult principle. It has a relationship with open/closed principle and contract by design. LSP guarantees that every object of subclasses behaves just like superclass. In this blog post I will explain what LSP is and how it helps to make better code.
"Software entities should be open for extension, but closed for modification" is the definition of open/closed principle. I learned a lot while writing this blog post. For example I learned what relationship does open/closed principle have with strategy pattern. I will explain also it beside I explain what is the open/closed principle.
This is the 2/5 blog post from SOLID serie. It was worth to write!