Does everybody agree about the “Principles Of Object Oriented Design” ?
The first five principles are principles of class design. They are:
|SRP||The Single Responsibility Principle||A class should have one, and only one, reason to change.|
|OCP||The Open Closed Principle||You should be able to extend a classes behavior, without modifying it.|
|LSP||The Liskov Substitution Principle||Derived classes must be substitutable for their base classes.|
|DIP||The Dependency Inversion Principle||Depend on abstractions, not on concretions.|
|ISP||The Interface Segregation Principle||Make fine grained interfaces that are client specific.|
The next six principles are about packages. In this context a package is a binary deliverable like a .jar file, or a dll as opposed to a namespace like a java package or a C++ namespace.
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 together.|
The last three principles are about the couplings between packages, and talk about metrics that evaluate the package structure of a system.
|ADP||The Acyclic Dependencies Principle||The dependency graph of packages must have no cycles.|
|SDP||The Stable Dependencies Principle||Depend in the direction of stability.|
|SAP||The Stable Abstractions Principle||Abstractness increases with stability.|