vault backup: 2025-01-17 15:08:14

5 Media/8 Courses/Design Patterns by Construx.md

@@ -234,7 +234,28 @@ Build a wrapper around a complex service to simplify the interface.
 - High cohesion / loose coupling (secondary, decouple the service provider)
 ### Bridge
 **Prerequisite**: Adapter Pattern
+Remember the fundamental design pattern of favouring association over inheritance. In a CNC-milling machine example we have 60 different subclasses of a programStep, which all cut different cuts. If I want to add a new communication protocol to communicate with the machine (tcp instead of serial) I would have to add another layer which adds another 60 subclasses, and so forth. This would be really bad and this is where the bridge pattern thrives:
 
+Goal force: decouple abstraction from implementation so that the two can vary independently. There are variations on two dimensions: the type of cut, the type of communication.
+Constraint force: layer of indirection: slight performance hit
+
+**Abstraction and Implementation can vary independently!**
+
+![[Pasted image 20250117141550.png]]
+
+Bridge is often inherently an Adapter.
+
+> [!NOTE] No definition of how "abstractions" get bound to "implementors"
+> - statically at "abstraction" instantiation
+> - dynamically as parameter or dependency injection?
+
+#### Design principles
+- favor association over inheritance
+- high coehision/ loose coupling
+- design to invariants / design for change
+- liskov substitutability
+
+![[Pasted image 20250117142732.png]]
 ### Strategy
 
 ### Composite