Structural Design Patterns
Structural Design Patterns in Python
Structural patterns explain how to assemble objects and classes into larger structures while keeping these structures flexible and efficient.
1. Adapter Pattern
The Adapter pattern allows objects with incompatible interfaces to collaborate.
1.1 Example: Legacy Data System Adapter
1.2 Benefits of Adapter
- Integrates incompatible interfaces
- Improves reusability of existing code
- Enhances flexibility in system design
2. Bridge Pattern
The Bridge pattern separates an object’s abstraction from its implementation, allowing them to vary independently.
2.1 Example: Cross-Platform Shape Drawing
2.2 Benefits of Bridge
- Decouples abstraction from implementation
- Improves extensibility
- Hides implementation details from clients
3. Composite Pattern
The Composite pattern lets you compose objects into tree structures and then work with these structures as if they were individual objects.
3.1 Example: File System Structure
3.2 Benefits of Composite
- Simplifies client code when working with complex hierarchies
- Makes it easy to add new types of components
- Provides flexibility in structuring data
4. Decorator Pattern
The Decorator pattern lets you attach new behaviors to objects by placing these objects inside special wrapper objects that contain the behaviors.
4.1 Example: Coffee Ordering System
4.2 Benefits of Decorator
- Adds responsibilities to objects dynamically
- Provides a flexible alternative to subclassing
- Allows for a mix-and-match approach to adding features
5. Facade Pattern
The Facade pattern provides a simplified interface to a complex subsystem.
5.1 Example: Home Theater Facade
5.2 Benefits of Facade
- Simplifies interface to a complex subsystem
- Decouples client code from subsystem
- Provides a context for usage
6. Flyweight Pattern
The Flyweight pattern lets you fit more objects into the available amount of RAM by sharing common parts of state between multiple objects instead of keeping all of the data in each object.
6.1 Example: Character Rendering in a Document
6.2 Benefits of Flyweight
- Reduces memory usage when dealing with a large number of similar objects
- Improves performance in applications with many objects
- Centralizes state for many virtual objects
7. Proxy Pattern
The Proxy pattern lets you provide a substitute or placeholder for another object. A proxy controls access to the original object, allowing you to perform something either before or after the request gets through to the original object.
7.1 Example: Lazy Loading Image Proxy
7.2 Benefits of Proxy
- Controls access to the original object
- Can manage the lifecycle of the original object
- Adds a level of indirection for distributed, controlled, or intelligent access
Conclusion
Structural design patterns provide various ways to organize code for better structure, flexibility, and efficiency. They help in creating relationships between entities, making systems easier to maintain and extend. By understanding and applying these patterns, developers can create more robust and scalable software architectures.