CPSA Software Design Principles 4

Question 1

Interface Segregation Principle (ISP) recommends that clients should NOT be forced to depend on interfaces they do not use. What is the PRIMARY design remedy?

Accepted Answer

Split large interfaces into smaller, role-specific ones

Answer

ISP recommends splitting fat interfaces into multiple focused, role-specific interfaces so clients only depend on the methods they actually use.

Question 2

Which term describes the degree to which elements within a module belong together and relate to a single purpose?

Accepted Answer

Cohesion

Answer

Cohesion measures how closely related and focused the responsibilities of a single module are — high cohesion means all elements serve a common purpose.

Question 3

Preferring composition over inheritance is recommended primarily because composition:

Accepted Answer

Avoids breaking changes when parent class internals change

Answer

Composition avoids the fragile base class problem — changes to a parent class cannot break subclasses because composed objects are accessed through interfaces, not inherited directly.

Question 4

What quality attribute is MOST directly improved by applying abstraction in software design?

Accepted Answer

Modifiability / maintainability

Answer

Abstraction hides implementation details behind stable interfaces, making it easier to change internals without affecting dependent components, directly improving modifiability.

Question 5

Which scenario is an example of 'feature envy' as a code smell related to design principles?

Accepted Answer

A method that uses data and methods from another class more than its own

Answer

Feature envy occurs when a method accesses another object's data far more than its own class's data, suggesting the method may belong in the other class.

CPSA Exam Practice Test

CPSA Exam Practice Test

CPSA Software Design Principles 4