Design Patterns

Design Patterns Expertise

Design patterns provide reusable solutions to commonly occurring problems in software design. I apply patterns judiciously to improve code quality, maintainability, and extensibility while avoiding over-engineering.

Creational Patterns

• Singleton: Implementing thread-safe singleton patterns using double-check locking, Lazy<T>, or dependency injection container. Understanding when singleton is appropriate and avoiding global state anti-patterns.

  Using singleton for logging, configuration, and caching scenarios. Recognizing when singleton becomes problematic and preferring dependency injection alternatives.

• Factory & Abstract Factory: Creating objects through factory methods and abstract factories to decouple object creation from usage. Implementing factory patterns for dependency injection and testability.

  Using factories to encapsulate complex object creation logic, support multiple implementations, and enable runtime selection of concrete types. Applying abstract factories for product families and platform-specific implementations.

• Builder: Constructing complex objects step-by-step using builder pattern for improved readability and flexibility. Implementing fluent interfaces and method chaining for expressive object construction.

  Using builders for configuration objects, query builders, and complex domain models. Leveraging C# object initializers and record types where builder pattern adds unnecessary complexity.

Structural Patterns

• Adapter: Bridging incompatible interfaces by creating adapters that translate between different APIs. Using adapters for third-party library integration and legacy system modernization.

  Implementing adapter pattern for data transformation, API wrappers, and interface compatibility. Recognizing when adapter is needed versus refactoring interfaces.

• Decorator: Adding behavior to objects dynamically through composition. Implementing decorators for cross-cutting concerns like logging, caching, and validation.

  Using decorators with dependency injection to enhance service behavior without modifying existing code. Applying decorator pattern for aspect-oriented programming scenarios.

• Facade: Providing simplified interfaces to complex subsystems. Creating facades that hide implementation complexity and provide cohesive APIs to clients.

  Using facades to encapsulate framework usage, third-party integrations, and internal system complexity. Balancing facade simplicity with flexibility needs.

Behavioral Patterns

• Observer: Implementing event-driven communication using observer pattern and C# events/delegates. Using IObservable/IObserver interfaces for reactive programming scenarios.

  Applying observer pattern for UI updates, notification systems, and publish-subscribe messaging. Understanding event subscription management and avoiding memory leaks.

• Strategy: Encapsulating algorithms and making them interchangeable at runtime. Using strategy pattern with dependency injection for algorithm selection and testability.

  Implementing strategies for payment processing, validation rules, and business rule engines. Leveraging C# delegates and function pointers where appropriate.

• Command: Encapsulating requests as objects to support undo operations, queuing, and logging. Implementing command pattern for workflow engines and action history.

  Using commands for API requests, user actions, and asynchronous task execution. Supporting command composition, macro commands, and transaction-like operations.

Pattern Application

• Context Awareness: Understanding when to apply patterns versus when simpler solutions suffice. Avoiding pattern overuse that increases complexity without clear benefits.

  Evaluating trade-offs between patterns and direct implementation. Choosing patterns that align with team familiarity and project requirements.

• Modern C# Alternatives: Leveraging C# language features that reduce need for certain patterns. Using records for value objects, pattern matching for visitor pattern scenarios, and async/await for async patterns.

  Adapting traditional patterns to modern C# idioms and functional programming concepts. Combining patterns with language features for elegant solutions.