Improve Your Software with SOLID Code

You might have heard of the acronym SOLID and the five principles it consists of. Sadly the concepts are very abstract and can be difficult to really understand, while they are so important to writing good object oriented code. This talk will not only deal with the theory behind SOLID and explain why SOLID is important. Better yet, we will be looking at code (lots of it!) and how it can be improved by applying one of the SOLID principles.

Transcript

1. AmsterdamPHP 18-10-2012 SOLID Software
3. AmsterdamPHP 18-10-2012 SOLID
4. Solid Single Responsibility Principle There should never be more than one reason for a class to change.
8. Solid Single Responsibility Principle The most simple principle to understand, the hardest to get right
9. sOlid Open Closed Principle Software entities (classes, modules, functions, etc) should be open for extension, but closed for modification.
12. sOlid A better solution
16. sOlid Getting the Api
18. sOlid One switch rule
21. sOlid Diving in deeper
26. sOlid Open Closed Principle 1. Since changing code introduces errors 2. Try to minimize change
27. soLid Liskov Substition Principle Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it
33. soLid Design by contract
34. soLid Liskov Substition Principle 1. Indispensable when adhering to the OCP 2. Only when a subclass can be used as its parent in every respect, functions using that parents can be reused without impunity.
35. solId Interface Segregation Principle Clients should not be forced to depend upon interfaces that they do not use.
40. solId Interface Segregation Principle 1. Design interfaces based on use-cases 2. Stop pollution from seeping in
41. soliD Dependency Inversion Principle 1. High-level modules should not depend on low level modules. Both should depend on abstractions. 2. Abstractions should not depend upon details. Details should depend upon abstractions.
45. soliD Dependency Inversion Principle != Dependency Injection
46. soliD Dependency Inversion Principle 1. Implementation details hide behind abstractions 2. Other code depends upon these abstractions
47. AmsterdamPHP 18-10-2012 Single responsibility principle Open closed principle Liskov subtitution principle Interface segregation principle Dependency inversion principle
48. AmsterdamPHP 18-10-2012 http://joind.in/talk/view/7293 www.freeklijten.nl @flijten