What is the difference between Singleton and Factory design patterns?

What is the difference between Singleton and Factory design patterns?

The Singleton pattern ensures a class has only one instance and provides a global point of access to it. In contrast, the Factory pattern is used to create objects without specifying the exact class of object that will be created.

Can you give me an example of each pattern?

Sure! For Singleton, think of a configuration manager that loads settings once and provides access throughout the app. For Factory, consider a shape factory that creates different shapes like circles or squares based on input.

When should I use each pattern?

Use Singleton when you need a single instance for shared resources, like logging. Use Factory when you want to decouple object creation from usage, allowing for flexibility in object types.

Are there any drawbacks to using these patterns?

Yes, Singleton can introduce global state, making testing harder. Factory can add complexity if overused, leading to unnecessary abstraction.