The document discusses the Single Responsibility Principle (SRP), which states that a class should have one, and only one, reason to change. This is one of the SOLID principles for object-oriented design. The SRP helps reduce coupling between classes and makes code more maintainable by separating concerns. Examples are provided to illustrate refactoring code according to the SRP.

1. Design patterns: The
Single-Responsibility
Principle
Grzegorz Wilczyński 11th november 2012

2. SOLID
The principles when applied
together intend to make it more
likely that a programmer will
create a system that is easy to
maintain and extend over time.
http://en.wikipedia.org/wiki/Solid_(object-oriented_design)

3. SOLID
Single responsibility
Open-closed
Liskov substitution
Interface segregation
Dependency inversion
http://en.wikipedia.org/wiki/Solid_(object-oriented_design)

4. BIBLE
http://www.amazon.com/Agile-Principles-Patterns-Practices-C/dp/0131857258

5. Rule #1
A class should have only one
reason to change.
"Agile Principles, Patterns, and Practices in C#" Robert C. Martin

6. Rule #2
A class should have only one
reason to change.
"Agile Principles, Patterns, and Practices in C#" Robert C. Martin

7. So please don't...
http://3.bp.blogspot.com/-FQZ4VT_gbRY/T8RvXLTPWMI/AAAAAAAABP0/JCckSpENM88/s640/SingleResponsibilityPrinciple.jpg

8. Step 1
http://www.remondo.net/wp-content/uploads/2012/03/SingleResponsibilityPrincipleRadio.png

9. Step 2
http://www.remondo.net/wp-content/uploads/2012/03/SingleResponsibilityPrincipleRadioManagers.png

10. Homework
$ git branch gw-solid-1
end time: 16.11.2012