Introduction to Design Patterns
Design patterns are typical solutions to common problems in software design. Each pattern is like a blueprint that you can customize to solve a particular design problem in your code. They are not finished designs that can be transformed directly into code but are templates for how to solve a problem in many different situations.
Why Use Design Patterns?
- Reusability: Design patterns provide solutions that can be reused in multiple projects.
- Efficiency: They help speed up the development process by providing tested, proven development paradigms.
- Communication: Design patterns provide a common language for developers, making it easier to communicate complex ideas.
Types of Design Patterns
Design patterns can be classified into three main categories:
- Creational Patterns: Deal with object creation mechanisms, trying to create objects in a manner suitable to the situation.
- Structural Patterns: Deal with object composition or the way to realize relationships between entities.
- Behavioral Patterns: Deal with object collaboration and the delegation of responsibilities among objects.
Common Design Patterns
- Singleton: Ensures a class has only one instance and provides a global point of access to it.
- Factory Method: Defines an interface for creating an object, but lets subclasses alter the type of objects that will be created.
- Observer: Defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
- Strategy: Defines a family of algorithms, encapsulates each one, and makes them interchangeable.
Further reading