Design Principles

Question

What principles do you generally follow when doing class design?

Answer 1

Principles Of Object Oriented Class Design (the "SOLID" principles)

• 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.
• ISP: The Interface Segregation Principle Make fine grained interfaces that are client specific.
• DIP: The Dependency Inversion Principle Depend on abstractions, not on concretions.

Source: http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod

Answer 2

Domain Driven Design is generally a good principle to follow.

Answer 3

The S.O.L.I.D. principles.
Or at least I try not to steer away too much from them.

Answer 4

Check out http://www.objectmentor.com/resources/publishedArticles.html

This is a good reference for design principles in general.

Answer 5

The "Resource Acquisition Is Initialization" paradigm is handy, particularly when writing in C++ and dealing with operating system resources (file handles, ports, etc.).

A key benefit of this approach is that an object, once created, is "complete" - there is no need for two-phase initialization and no possibility of partially-initialized objects.

Answer 6

I usually try to fit the class into one of the oo design patterns.

Answer 7

Basically I get away with programming to interfaces. I try to encapsulate that which changes through cases to avoid code duplication and to isolate code into managable (for my brain) chunks. Later, if I need, I can then refactor the code quite easily.

Answer 8

As mentioned above, some of the fundamental Object Oriented Design principles are OCP, LSP, DIP and ISP.

An excellent overview of these by Robert C. Martin (of Object Mentor) is available here: OOD Principles and Patterns

Answer 9

loosely coupled, highly cohesive.

Composition over inheritance.

Answer 10

Don't forget the Law of Demeter.

Answer 11

SOLID principles and Liskov's pattern, along with Single responsibility pattern.

Answer 12

The most fundamental design pattern should be KISS (keep it simple stupid) Which means that sometimes not using classes for some elements at all it the right solution.

That and CRC(Class, Responsibility, Collaborators) cards (write the card down in your header files, not on actual cards that way they because easy to understand documentation too)