Software Design Patterns Overview

Study Notes

Software Design Patterns

Software design patterns are solutions to recurring problems faced by developers when designing software systems. These patterns help codify best practices that have been proven effective over time and can be reused across different projects, helping to improve code quality and maintainability. There are three main types of design patterns: Creational, Structural, and Behavioral.

Creational Patterns

Creational patterns focus on how objects are created and managed, ensuring flexibility while avoiding unnecessary complexity. Some commonly used creational patterns include:

Factory Method: This pattern involves defining an interface for creating objects in a superclass, allowing subclasses to decide which class to instantiate. It decouples the client from the concrete classes and allows for dynamic object creation without requiring knowledge of the implementations.
Abstract Factory: This pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes until runtime. It helps manage dependencies between objects and promotes modularity.
Singleton: As its name implies, this pattern ensures that only one instance of a particular class is ever created and provides a global access point for this unique instance. It's useful when you want to ensure that there is exactly one instance of a class.

Structural Patterns

Structural patterns are concerned with the organization of classes and objects, providing a way to organize and manage complexity. Some common structural patterns include:

Adapter: This pattern provides a way to use an existing class within another system by adding a layer between them that translates interfaces to make them compatible.
Facade: A facade simplifies complex systems by providing a unified interface over many subsystems through delegation.
Decorator: This pattern allows functionality to be added to an individual object without altering its structure.

Behavioral Patterns

Behavioral patterns are concerned with how objects communicate with each other and organize their interactions. Some commonly used behavioral patterns are:

Template Method: This design pattern defines a skeleton algorithm in an abstract superclass, allowing subclasses to override specific steps of the algorithm without having to redefine the entire method.
Strategy: This pattern encapsulates algorithms into objects called strategies, which can then be selected at runtime based on the context of the program.
Observer: Also known as Publish-Subscribe, this pattern decouples objects by moving event handling logic from classes directly to the clients of those classes.

Understanding and applying these patterns helps developers create applications that are more flexible, maintainable, and scalable. By leveraging these solutions to recurring issues, they can avoid common pitfalls and build software that meets business requirements while minimizing technical debt.

Description

Learn about the three main types of software design patterns - Creational, Structural, and Behavioral - and how they provide solutions to common problems in software development. Explore examples of creational patterns like Factory Method, Structural patterns like Adapter, and Behavioral patterns like Observer. Understanding and applying these patterns can improve code quality, maintainability, and scalability in software projects.