Design Patterns and Frameworks Project

🎯 Overview

This comprehensive Java project demonstrates the implementation of 16 classic GoF (Gang of Four) design patterns along with advanced features including performance monitoring, testing techniques, and pattern combinations. The project serves as both a learning resource and a practical reference for software design patterns.

📊 Project Statistics

• 23 Design Patterns implemented (Complete GoF Collection)
• 6 Advanced Features for monitoring and testing
• 3 Categories of patterns (Creational, Structural, Behavioral)
• 100% English documentation and code
• Professional-grade implementations with validation and error handling

🏗️ Pattern Categories

Creational Patterns (6)

• Singleton - Global instance management
• Factory Method - Object creation delegation
• Builder - Complex object construction
• Abstract Factory - Family of related objects
• Prototype - Object cloning
• Improved Singleton - Thread-safe variations

Structural Patterns (7)

• Adapter - Interface compatibility
• Bridge - Abstraction-implementation separation
• Composite - Tree structure handling
• Decorator - Dynamic responsibility addition
• Facade - Simplified subsystem interface
• Flyweight - Memory optimization through sharing
• Proxy - Access control and lazy loading

Behavioral Patterns (11)

• Chain of Responsibility - Request processing chain
• Command - Request encapsulation
• Iterator - Collection traversal
• Mediator - Object interaction management
• Memento - State preservation
• Observer - Event notification system
• State - State-dependent behavior
• Strategy - Algorithm encapsulation
• Template Method - Algorithm skeleton
• Visitor - Operation separation from structure

🚀 Advanced Features

• Pattern Combinations - Real-world pattern integration
• Performance Benchmarks - Execution time and memory analysis
• Improved Builder - Validation and immutability
• Performance Monitoring - Real-time metrics collection
• Advanced Testing - Property-based and thread safety testing

📋 Prerequisites

• Java 8 or higher
• Apache Maven 3.6+
• Git (for cloning)

🛠️ Installation

1. Clone the repository:

   git clone <repository-url>
   cd "Design Pattern et Frameworks"

2. Compile the project:

   mvn clean compile

3. Verify installation:

   java -cp "target/classes" ch.hearc.patterns.Main

🎮 Usage

Quick Start

# See all available options
java -cp "target/classes" ch.hearc.patterns.Main

# Run a specific pattern
java -cp "target/classes" ch.hearc.patterns.Main singleton
java -cp "target/classes" ch.hearc.patterns.Main factory
java -cp "target/classes" ch.hearc.patterns.Main builder

# Run all patterns
java -cp "target/classes" ch.hearc.patterns.Main all

# Complete demonstration
java -cp "target/classes" ch.hearc.patterns.Main demo

Available Commands

Command	Description
singleton	Singleton pattern demonstration
factory	Factory Method pattern
builder	Builder pattern
abstract	Abstract Factory pattern
prototype	Prototype pattern
singleton+	Improved Singleton patterns
adapter	Adapter pattern
bridge	Bridge pattern
composite	Composite pattern
decorator	Decorator pattern
observer	Observer pattern
strategy	Strategy pattern
command	Command pattern
state	State pattern
template	Template Method pattern
chain	Chain of Responsibility pattern
combinations	Pattern combinations demo
benchmark	Performance benchmarks
improved	Improved Builder pattern
monitoring	Performance monitoring
testing	Advanced testing techniques
demo	Complete demonstration
all	Execute all patterns

📁 Project Structure

src/main/java/ch/hearc/patterns/
├── creation/           # Creational patterns (6 files)
│   ├── Singleton.java
│   ├── FactoryMethod.java
│   ├── Builder.java
│   ├── AbstractFactory.java
│   ├── PrototypeDemo.java
│   └── SingletonImproved.java
├── structural/         # Structural patterns (5 files)
│   ├── Adapter.java
│   ├── AdapterDemo.java
│   ├── Bridge.java
│   ├── Composite.java
│   └── Decorator.java
├── behavioral/         # Behavioral patterns (7 files)
│   ├── Observer.java
│   ├── ObserverDemo.java
│   ├── Strategy.java
│   ├── Command.java
│   ├── State.java
│   ├── TemplateMethod.java
│   └── ChainOfResponsibility.java
├── examples/           # Pattern examples (2 files)
│   ├── PatternDemo.java
│   └── PatternCombinations.java
├── benchmarks/         # Performance analysis (1 file)
│   └── PatternBenchmark.java
├── improvements/       # Advanced implementations (3 files)
│   ├── BuilderImprovements.java
│   ├── PerformanceMonitoring.java
│   └── AdvancedTesting.java
└── Main.java          # Application entry point

docs/                  # Documentation
├── DESIGN_PATTERNS_REFERENCE.md
├── PATTERN_INDEX.md
└── [Individual pattern docs]

📚 Documentation

Main Documentation

• Design Patterns Reference - Complete guide with detailed explanations
• Pattern Index - Quick reference for all patterns

Individual Pattern Documentation

Each pattern has its own detailed documentation in the docs/ directory with:

• Purpose and motivation
• Implementation details
• Usage examples
• When to use the pattern
• Code examples

🔧 Key Features

Professional Implementation

• Thread-safe Singleton implementations
• Input validation in Builder pattern
• Error handling throughout the codebase
• Immutable objects where appropriate
• Comprehensive testing with multiple approaches

Performance Analysis

• Real-time metrics collection
• Memory usage tracking
• Execution time measurement
• Performance comparison between patterns
• Caching strategies demonstration

Advanced Testing

• Property-based testing for invariants
• Thread safety testing for concurrent access
• Integration testing for pattern combinations
• Contract testing for behavioral verification

🎯 Learning Path

Beginner Level

1. Start with java -cp "target/classes" ch.hearc.patterns.Main demo
2. Explore individual patterns: singleton, factory, builder
3. Read the documentation in docs/ directory

Intermediate Level

1. Study pattern combinations: combinations
2. Analyze performance: benchmark
3. Explore advanced implementations: improved

Advanced Level

1. Dive into monitoring: monitoring
2. Study testing techniques: testing
3. Examine the source code for implementation details

🏆 Best Practices Demonstrated

1. SOLID Principles - Single Responsibility, Open/Closed, etc.
2. Design Principles - DRY, KISS, YAGNI
3. Code Quality - Proper error handling, validation, documentation
4. Performance - Efficient implementations with monitoring
5. Testing - Comprehensive test coverage with multiple approaches
6. Documentation - Clear, professional documentation

🔍 Pattern Selection Guide

Problem	Recommended Pattern
Need single instance	Singleton
Complex object creation	Builder
Object family creation	Abstract Factory
Algorithm selection	Strategy
Event notification	Observer
Request processing	Chain of Responsibility
Interface compatibility	Adapter
Dynamic behavior	Decorator

🚀 Performance Considerations

• Singleton - Fastest access, minimal memory
• Factory Method - Moderate overhead, high flexibility
• Builder - Higher overhead, excellent for complex objects
• Observer - Event-driven, scalable
• Strategy - Runtime flexibility, moderate overhead

🧪 Testing Strategy

• Unit Tests - Individual pattern behavior
• Integration Tests - Pattern combinations
• Performance Tests - Execution time and memory usage
• Thread Safety Tests - Concurrent access scenarios
• Property Tests - Invariant verification

📈 Monitoring and Metrics

• Execution Time - Nanosecond precision
• Memory Usage - Real-time tracking
• Thread Safety - Concurrent access monitoring
• Performance Ratios - Pattern comparison
• Caching Efficiency - Hit/miss ratios

🤝 Contributing

This project is designed for educational purposes. To contribute:

1. Follow the existing code style
2. Add comprehensive documentation
3. Include performance benchmarks
4. Provide usage examples
5. Test thoroughly

📄 License

This project is for educational purposes. All code and documentation are provided as-is for learning design patterns.

🎓 Educational Value

This project serves as:

• Learning Resource - Comprehensive pattern implementations
• Reference Guide - Quick access to pattern solutions
• Performance Guide - Understanding pattern trade-offs
• Best Practices - Professional implementation standards
• Testing Examples - Advanced testing techniques

🔗 Related Resources

• GoF Design Patterns Book
• Java Design Patterns
• Refactoring Guru

---

Happy Learning! 🚀

This project demonstrates professional-grade design pattern implementations with comprehensive documentation, testing, and performance analysis.