Few years back, I wrote a simple logging library in ActionScript3 using the Chain of Responsibility pattern. Recently, I dug up the old codes, made some modifications, and put it in github for other people to use and contribute. In this post, I will mainly focus on how to use the library and do some project specific modifications, but I will also briefly discuss my reasons for using the Chain Of Responsibility and the Singleton Pattern. I started writing this library with the following 4 goals in mind:
- It should be easily accessible to all of the classes of a project.
- It should be able to write logging information to different output sources, i.e., file, database, console, etc., and additional output sources can be added easily.
- It should be able to handle different levels of logging like FATAL_ERROR or INFO (as different actions may be needed for handling different levels), and additional levels can be added easily.
- It should require minimal setup.
Despite all its criticism, singletons still exists today, perhaps because insecure programmers feel the illusion of doing the “right” thing, since they are after all using a design pattern. For those who think, “What experts do, must be right”, I will leave a famous quote by Christopher Hitchens-
Picture all experts as if they were mammals. … Seek out argument and disputation for their own sake.
The popularity of the word ‘singleton’ probably comes from set theory, where it is a set with exactly one element. Similar to its mathematical counterpart, a singleton pattern in software engineering ensures exactly one instance of a class for each running application. This is how you would write a singleton class in Java: Continue reading