Encapsulation/Abstraction

Encapsulation

Encapsulation is the concept of bundling related data and behavior within a single entity.

Abstraction

Abstraction refers to information hiding.

• Users do not need to know or care about the internal workings of a system to use it through its public interface.

• Example: A doorknob provides a simple interface (Turn()) without exposing its internal mechanism.

Guidelines

• All data members should be private.

• Methods needed only by other methods should be private.

• Only methods required by other classes should be public or protected.

• Public methods should avoid implementation details.

  • Example: Use Save() instead of SaveToDatabase() to prevent a leaky abstraction.

• Public method signatures should remain stable.

  • Changing them requires updating all dependencies.

See Also:

• Pillars of OOP

• Minimize Accessibility of Classes and Members

• Some Object-Oriented Design Heuristics - Riel updated (Heuristics 2.1, 2.2, 2.5, 2.6, 5.3)

• Find What Is Varying and Encapsulate It (Shalloway 123)