Design Patterns Catalog (Swift)

A comprehensive collection of classic Design Patterns implemented in Swift. This project demonstrates 22 fundamental patterns organized into three categories: Creational, Structural, and Behavioral patterns.

📋 Table of Contents

• About
• Pattern Categories
• Project Structure
• Requirements
• Usage
• Patterns Overview
• Contributing
• License

🎯 About

This repository serves as a practical reference and learning resource for software developers who want to understand and implement design patterns in Swift. Each pattern is implemented with clear, well-documented code that follows best practices and Swift idioms.

Design patterns are reusable solutions to common problems in software design. They represent best practices evolved over time by experienced software developers.

📦 Pattern Categories

Creational Patterns (5)

Patterns that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation.

Structural Patterns (7)

Patterns that ease the design by identifying a simple way to realize relationships between entities.

Behavioral Patterns (10)

Patterns that identify common communication patterns between objects and realize these patterns.

📁 Project Structure

PatternsCatalog/
├── Creational/
│   ├── AbstractFactory.swift
│   ├── Builder.swift
│   ├── FactoryMethod.swift
│   ├── Prototype.swift
│   └── Singleton.swift
├── Structural/
│   ├── Adapter.swift
│   ├── Bridge.swift
│   ├── Composite.swift
│   ├── Decorator.swift
│   ├── Facade.swift
│   ├── Flyweight.swift
│   └── Proxy.swift
├── Behavioral/
│   ├── ChainOfResponsibility.swift
│   ├── Command.swift
│   ├── Iterator.swift
│   ├── Mediator.swift
│   ├── Memento.swift
│   ├── Observer.swift
│   ├── State.swift
│   ├── Strategy.swift
│   ├── TemplateMethod.swift
│   └── Visitor.swift
├── TestCreationalBundle/
├── TestStructuralBundle/
├── TestBehavioralBundle/
└── main.swift

💻 Requirements

• Xcode: 12.0 or later
• Swift: 5.0 or later
• macOS: 10.15 or later

🚀 Usage

1. Clone the repository:

   git clone https://github.com/yourusername/PatternsCatalog.git
   cd PatternsCatalog

2. Open the project:

   open PatternsCatalog.xcodeproj

3. Build and run:

   • Select the target scheme in Xcode
   • Press Cmd + R to build and run
   • Or run tests with Cmd + U

4. Explore individual patterns: Each pattern file contains:

   • Detailed comments explaining the pattern
   • Complete implementation
   • Client code demonstrating usage

📚 Patterns Overview

Creational Patterns

Pattern	Purpose
Abstract Factory	Creates families of related objects without specifying their concrete classes
Builder	Constructs complex objects step by step
Factory Method	Defines an interface for creating objects, but lets subclasses decide which class to instantiate
Prototype	Creates new objects by copying existing ones
Singleton	Ensures a class has only one instance and provides a global access point

Structural Patterns

Pattern	Purpose
Adapter	Allows incompatible interfaces to work together
Bridge	Separates abstraction from implementation
Composite	Composes objects into tree structures to represent part-whole hierarchies
Decorator	Adds new functionality to objects dynamically
Facade	Provides a simplified interface to a complex subsystem
Flyweight	Reduces memory usage by sharing common data between objects
Proxy	Provides a surrogate or placeholder for another object

Behavioral Patterns

Pattern	Purpose
Chain of Responsibility	Passes requests along a chain of handlers
Command	Encapsulates a request as an object
Iterator	Provides a way to access elements of a collection sequentially
Mediator	Reduces coupling between components by making them communicate through a mediator
Memento	Captures and restores an object's internal state
Observer	Defines a subscription mechanism to notify multiple objects about events
State	Allows an object to alter its behavior when its internal state changes
Strategy	Defines a family of algorithms and makes them interchangeable
Template Method	Defines the skeleton of an algorithm in a base class
Visitor	Separates algorithms from the objects on which they operate

🤝 Contributing

Contributions are welcome! If you'd like to add more patterns, improve existing implementations, or fix bugs:

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingPattern)
3. Commit your changes (git commit -m 'Add some AmazingPattern')
4. Push to the branch (git push origin feature/AmazingPattern)
5. Open a Pull Request

📄 License

This project is available for educational and reference purposes. Feel free to use and modify the code for your learning and projects.

📖 Further Reading

• Design Patterns: Elements of Reusable Object-Oriented Software (Gang of Four)
• Refactoring.Guru - Design Patterns
• Swift.org Documentation

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