So I just delved into the Singleton classes and yes, I find them quite helpful. I use my singletons mostly for data storage for multiple targets (views, tables etc.). That being said, I can already see myself going to implement a lot of singletons in my project.
But can a lot of singletons have a negative impact? From what I’ve read about singletons is that you create one instance for each of them in a proces. Other class instances get released (assuming they get released properly) from memory, then should singletons be released too?
So to narrow it down to one question: Is it harmful to have a lot of singletons?
Singletons don’t scale. No matter what you think should be a singleton, when your system gets bigger, it turns out you needed more than one.
If you NEVER need more than one, a singleton is fine. However, as systems scale, you typically need more than one of anything within its own context.
Singletons are merely another way to say “global”. It’s not bad, but generally, it’s not a good idea for systems that evolve and grow in complexity.