Cohesion and coupling
On This Lesson 4 topics
The content for this lesson is written and waiting for review. The outline below shows what it covers. It will be published once it is approved.
In this lesson
judge how well a class is built.
Planned topics
- Cohesion: do the parts of a class belong together? High cohesion is good.
- Coupling: how much does one class depend on others? Low coupling is good.
- Like a workshop: tools for one job in one drawer, and little need to walk between rooms.
- Reduce coupling: depend on a small interface, not on a concrete class; hide details.
- A class that does many unrelated things has low cohesion; split it.
Draft outline details
Demonstration
a diagram of CheckoutService linked to five concrete classes, then to two interfaces.
Check your understanding
Which do you want: high or low coupling?
Show answer
Low coupling, high cohesion.
Practice
Apply this lesson with the module's lab, exercises and quiz.
Marking a lesson complete is optional and you can undo it any time. Your progress stays in this browser.