Designing Building Blocks Flashcards

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

Answer: Component diagram

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

The 'required interface' of a building block represents:

Answer: The services the block needs from other blocks to function

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

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

Answer: Programming to interfaces rather than implementations

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

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

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

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

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

Answer: To provide a simplified interface to a complex set of subsystems

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

Which of the following BEST describes the concept of 'information hiding' in building block design?

Answer: Concealing implementation details behind a stable interface

Information hiding means implementation decisions are concealed behind an interface, limiting the impact of internal changes on other blocks.

When designing building blocks, why should circular dependencies be avoided?

Answer: They make blocks impossible to test or reuse independently

Circular dependencies bind blocks together so neither can be tested, replaced, or reused without the other, undermining modularity.