The Principles of OOD - 로버트 마틴

The first five principles are principles of class design. They are :

SRP	The Single Responsiblity Principle	“A class should have one, and only, one reason to change.“
OCP	The Open Closed Principle	You shloud be able to extend a classes behavior, without modifying it.
LSP	The Liskov Substitution Principle	Derived classes must be substitutable for their base classes.
ISP	The Interface Segeregation Principle	Make fine grained interfaces that are client specific.
DIP	The Dependency Inversion Principle	Depend on abstraction, not on concretions.

추가 설명

OCP - Software entities (classes, modules, etc) should be open for extension, but closed for modification.
LSP - Derived classes must usable through the base class interface without the need for the user to know the difference
DIP

A. High-level modules should not depend on low-level modules. Both should depend on abstractions.

B. Abstractions should not depend on details. Details should depend on abstractions.

The next six principles are about packages.

The first three package principles are about package cohesion, they tell us what to put inside packages:

REP	The Release Reuse Equivalency Principle	The granule of reuse is the granule of release.
CCP	The Common Closure Principle	classes that change together are packaged together.
CRP	The Common Reuse Principle	classes that are used together are packaged toghether.

추가 설명

REP - The granule of reuse is the same as the granule of release. Only components that are released through a tracking system can be effectively reused.
CCP - Classes within a released component should share common closure. That is, if one needs to be changed, they all are likely to need to be changed. What affects one, affects all.
CRP - Classes within a released componen should be reused together. That is, it is impossible to separate the components from each other in order to reuse less than the total.