Pattern Design Ultimate Design Pattern 4

Question 1

In the Strategy pattern, what is the relationship between the Context and the Strategy interface?

Accepted Answer

Context holds a reference to a Strategy object and delegates behavior to it

Answer

Context aggregates a Strategy via composition and delegates the algorithm to it, making the algorithm easily swappable at runtime.

Question 2

Which pattern provides a surrogate or placeholder for another object to control access to it?

Accepted Answer

Proxy

Answer

The Proxy pattern wraps an object to control access, add lazy initialization, logging, caching, or remote communication.

Question 3

What distinguishes the Abstract Factory pattern from the Factory Method pattern?

Accepted Answer

Factory Method uses inheritance; Abstract Factory uses composition to produce families of related objects

Answer

Abstract Factory provides an interface for creating families of related objects, while Factory Method delegates creation of a single product to subclasses via inheritance.

Question 4

Which design pattern is best suited when you need to decouple many-to-many communications between objects by centralizing all interaction through one object?

Accepted Answer

Mediator

Answer

The Mediator pattern reduces chaotic dependencies between many objects by routing all communication through a central mediator object.

Question 5

In which scenario is the Builder pattern most appropriate compared to a simple constructor?

Accepted Answer

When creating an object requires many optional parameters or a multi-step construction process

Answer

Builder shines when constructing complex objects step by step, avoiding telescoping constructors or partially initialized objects.

Pattern Design Practice Test

Pattern Design Practice Test

Pattern Design Ultimate Design Pattern 4