Provider pattern practices
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This document discusses design patterns including the provider pattern. It begins by listing some object-oriented programming principles and software architecture patterns. It then focuses on the open-closed principle and how the provider pattern adheres to this principle by allowing new types to be added without modifying existing code. The provider pattern works by dynamically creating instances of classes based on external configuration settings, avoiding the need to modify code. This is compared to the factory pattern, which still requires in-code configuration and modification. Real-world examples of implementing the provider pattern are also provided.
Provider pattern practices
- 1. Provider Pattern practices MINH NGUYEN @LINKNODE SEPTEMBER, 2015
- 2. Object-Oriented Programming 23 Design Patterns5 Principles Single responsibility Open/closed Liskov substitution Integrated segregation Dependency inversion Software Architecture 3-tier MVC MVP MVVM ….
- 3. Open-closed principle “Software modules should be closed for modifications but open for extensions.” Sample use case: Requirements: VentusAR needs to supply a new model type: SolarPanel Current action: Have to modify all existing code everywhere to support this new type string message= “”; if (type = “Wind”) { message = “Turbine is spinning”; } else if (type = “SolarPanel”) { message = “Solar panel is under the sun”; } else if …. else if …. else if …. Violate Open-closed principle (having to modify existing code to be able to add new feature)
- 4. Inspired by Factory Pattern VentusModel + getMessage() Turbine + getMessage() SolarPanel + getMessage() Transmission + getMessage() VentusModelFactory + getInstant(name) creates Client asks products
- 5. Provider Pattern (Microsoft 2002) * Mimic Plug-in/ Add-on architecture * Do not have to modify existing code * Just supply additional separate class * Configure from external settings (config file, database,) Create instant from string
- 6. + External Settings Provider pattern From XML: From Database: string string
- 7. * Supply a new Transmission model to the app without modifying code Demo
- 8. Provider Pattern vs Factory Pattern ? * In-code config * Still have to modify existing code * Configure easily from external settings (using .Net Reflection) * Do not have to modify existing code
- 9. Q&A