CPSA Designing Building Blocks 3

Question 1

Which diagram type in UML is most commonly used to show the static structure of building blocks and their relationships?

Accepted Answer

Component diagram

Answer

UML component diagrams depict building blocks, their interfaces, and the dependencies between them at a structural level.

Question 2

The 'required interface' of a building block represents:

Accepted Answer

The services the block needs from other blocks to function

Answer

A required interface specifies which services from other building blocks are needed for the block to fulfill its responsibilities.

Question 3

Which strategy BEST reduces the impact of change when a building block's implementation must be replaced?

Accepted Answer

Programming to interfaces rather than implementations

Answer

Programming to interfaces isolates consumers from implementation details, so replacing an implementation does not affect dependent blocks.

Question 4

In a layered architecture, which rule governs how building blocks in different layers may interact?

Accepted Answer

Blocks may only depend on blocks in the same or lower layers

Answer

The layering rule requires that dependencies flow downward — a block may use blocks in the same layer or layers below it.

Question 5

What is a 'facade' building block used for in software architecture?

Accepted Answer

To provide a simplified interface to a complex set of subsystems

Answer

A facade provides a unified, simplified interface to a complex subsystem, hiding its internal complexity from clients.

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