OODP Review.

I took a three hour mini-course on OO Design Principles. Now, go brush up on your OODP and more of its acronyms.

1) Polymorphism: behavior that varies depending on the function’s class being invoked.
2) Hierarchy: a) Inheritance – allow a subclass to access members of the parent class. b) Aggregation – objects can contain one or more objects of another object.
3) Encapsulation: hide/reaveal particular details of a class.
4) Abstraction: hide the details of an subclass.
5) Objects/Classes: collection of characteristics that describe something whether it is abstract or tangible; object is an instance of a class.

SRP (Single Responsibility Principle): a class should be responsible for only one thing.
DRY (Don’t Repeat Yourself): self explanatory, don’t copy/paste.
LSP (Liskov Substitution Principle): “Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it.”
DIP (Dependency Inversion Principle): “High level modules should not depend upon low level modules. Both should depend on abastractions. Abstractions should not depend of details. Details should depend on abstractions.”
OCP (Open Closed Principle): Classes, methods, functions “should be open for extension, but closed for modification.”
ISP (Interface Segregation Principle): “Clients should not be forced to depend upon interfaces that they do not use.”
CCP (Common Closed Principle): “Classes within a released component should share common closure. If one need to be changed, they all are likely to need to be changed. What affects one, affects all.”
ADP (Acyclic Dependency Principle): The dependency structure for released component must be a Directed Acyclic Graph. There can be no cycles.”
SDP (Stable Dependency Principle): “Dependencies between released components must run in the direction of stability. The dependee must be more stable than the depender.”
SAP (Stable Abstraction Principle): “The more stable a component is, the more it must consist of abstract classes. A completely stable category should consist of nothing but abstract classes.”
RREP (Reuse/Release Equivalency Principle):“The granularity of reuse is the same as the granularity of release. Only components that are released through a tracking system can be effectively reused.”

If you want to read more about any of these, go check out ObjectMontor. They have a lot more documents and articles there to read.

I hope I’m not missing any important ones, if so add some to the list.

1 reply on “OODP Review.”

Most of those principles are harder to implement than they seem. It’s one thing to know the definition of a principle and another to know when and how to apply it to your design

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