Design Pattern in Apex

In Computer Science, a good design of a software is vital to accomplish complex business requirements, future extensibility and maintainability. While learning a programming language, beginners in most of the cases concentrate more on language syntax and usage techniques. But at the same time, it is also very important to understand the basics of good software design. 

This series is dedicated to all the Design Patterns in Apex. In each post, I will explain the pattern with it's importance, usage with business case. 

So let's start -

1. Implementing Singleton Design Pattern in Apex - Use Case I
2. Implementing Singleton Design Pattern in Apex - Use Case II
3. Implementing Singleton Design Pattern in Apex - Use Case III
4. Implementing Strategy Design Pattern in Apex
5. Implementing Decorator Design Pattern in Apex
6. Apex Trigger Design Pattern

Will appreciate if you can provide your valuable feedback. Thanks in advance.