Design patterns are a collection of software development best practices in solving commonly occurring problems.
Design patterns’ purpuse is to improve the software’s quality, reusability, and maintenability.
There are 4 categories of design patterns called Gang of Four (GoF):
- Creational patterns
- Structural patterns
- Behavior patterns
- Concurrency patterns
Singleton is a creational pattern.
Double-checked locking is a concurrency pattern.
Lazy initialization is a a creational pattern.
Singleton is a design pattern used to limit one class to have just only 1 instance.
Basic Singleton example:
Double-check locking singleton example:
volatile: ensures that one thread retrieves the most up-to-date value written by another thread.
Lazy initialization singleton example:
Call the methods inside the singleton classes.
The two implementations of singleton works, and you can choose the ideal one with your special requirements.
I hope this post does help to you. Enjoy coding!