Design Patterns GoF — Delphi

GoF design patterns in Delphi are implemented using interface-driven solutions and TInterfacedObject-based classes to enforce SOLID principles. This approach replaces ad-hoc implementations with structured, reusable object-oriented code across Creational, Structural, and Behavioral categories.

Delphi design pattern implementations require the T/I/E/F/A/L naming conventions for classes and interfaces, paired with robust memory management using try..finally blocks. This ensures disciplined resource handling and prevents memory leaks in object-oriented architectures.

You need the Factory pattern in Delphi when encapsulating object creation logic, and the Strategy pattern when swapping algorithms at runtime without modifying clients. Both enable clean separation of concerns and maintainable, testable code.

Yes, TInterfacedObject-based implementations are used to build Delphi Singleton and Observer classes. By leveraging interfaces, these patterns achieve reference-counted memory management and decoupled communication between objects.

The skill provides concrete Delphi examples for structural patterns including Adapter, Decorator, Facade, and Proxy. These patterns help adapt interfaces, add responsibilities dynamically, and simplify complex subsystem interactions.

The best way to separate concerns in Delphi is applying GoF behavioral patterns like Command, Template Method, State, and Chain of Responsibility. These patterns decouple request handling and state transitions for maintainable architectures.