Coupling | Cohesion — [Notes]
[Refer LLD Index for all LLD topics]
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· Coupling
· Cohesion
· Functional Cohesion / Capability Centric
∘ Single Responsibility Principle
· Informational Cohesion / Entity Centric
· Why low level code is organized by technical concerns?
· How to handle coupling between highly cohesive services?
· How to handle coupling between mixed responsibility in code?
· References
Coupling
“degree of interdependence between software modules
Cohesion
“degree to which the elements inside a module belong together” — Structured Design: Fundamentals of a Discipline of Computer Program and Systems Design
Functional Cohesion / Capability Centric
- Grouped related to operations of a task.
Single Responsibility Principle
- When you write a software module, you want to make sure that when changes are requested, those changes can only originate from a single person, or rather, a single tightly coupled group of people representing a single narrowly defined business function.
- You want to isolate your modules from the complexities of the organization as a whole, and design your systems such that each module is responsible (responds to) the needs of just that one business function.
source — https://blog.cleancoder.com/uncle-bob/2014/05/08/SingleReponsibilityPrinciple.html
Informational Cohesion / Entity Centric
- Can drive high degree of coupling.
- Focus will be on data instead of functional boundary
vs
Why low level code is organized by technical concerns?
MVC — Model + View + Controller | generally each one of them has 1:1 mapping with each other
vs
Organize by Feature
How to handle coupling between highly cohesive services?
How to handle coupling between mixed responsibility in code?
- Can use Pipes and Filters pattern [Russian Doll]
