Notes from Design Patterns Overview Pluralsight Course

I recently completed the Pluralsight course Design Patterns Overview by Steve Smith, which was very informative as a bird's eye view of design patterns as a general topic.

Why learn design patterns?

• So you don't reinvent the wheel
• They allow for increased clarity of communication
• They often lead to better software
• Advance your career

How to learn design patterns?

• be familiar with a wide array of patterns
• have a shallow understanding of several other patterns
• have a deep knowledge/mastery of several patterns

What makes up a design pattern?

• name/classification
• intent
• aka's
• motivation/problem to be solved
• applicability/context
• structure
• participants (classes, objects, etc.)
• collaboration between participants
• consequences/design tradeoffs
• implementation
• sample code
• known uses
• related patterns

Bolded points above indicate bare minimum required for broad knowledge of a particular pattern.

Design pattern structure

• Often described by a UML diagram

  • boxes represent classes or interfaces
  • lines represent some kind of relationship - inheritance, implementation, calls, etc.

When to apply design patterns?

• Practice with a coding exercise/kata, testing, repeat with variations

  • Gilded rose kata good for practicing Proxy pattern, Rules Engine pattern, Builder pattern, Template Method pattern
• In real code, follow refactoring fundamentals, make sure you have test coverage, do your work in a separate branch, and verify consistent behavior after completing the refactoring. Be prepared to delete what you've got and start over if this pattern really doesn't fit with this code

A few good design patterns in C#

• Strategy
• Repository - data-access pattern; works well with Strategy and other patterns
• Adapter
• Factory

• Proxy and Decorator patterns

  • closely related structurally but have different intents
  • work well with other patterns
• Singleton

Summary

• Design patterns = general solutions to existing problems
• Avoid reinventing the wheel
• Higher-level communication with your team
• T-shaped knowledge of patterns
• Practice!
• Use refactoring to apply patterns
• Look for ways to combine patterns

Thanks for reading! I hope you find this and other articles here at ilyanaDev helpful! Be sure to follow me on Twitter @ilyanaDev.

Tags

• software development
• coding
• design patterns
• pluralsight