Pattern Design Structural Design Patterns 2

Question 1

A Proxy pattern can be used to implement all of the following EXCEPT:

Accepted Answer

Converting incompatible interfaces

Answer

Converting incompatible interfaces is the role of the Adapter pattern, not Proxy — Proxy keeps the same interface but controls access to the real subject.

Question 2

Which structural pattern is most helpful when you want to add logging, caching, or security checks transparently?

Accepted Answer

Proxy

Answer

The Proxy pattern wraps a real object and intercepts calls to it, making it ideal for cross-cutting concerns like logging or caching.

Question 3

The Class Adapter pattern uses ________ while the Object Adapter uses ________.

Accepted Answer

Inheritance; composition

Answer

A Class Adapter inherits from both the target interface and the adaptee, while an Object Adapter wraps (composes) an instance of the adaptee.

Question 4

In the Composite pattern, what is the key characteristic of leaf nodes?

Accepted Answer

They have no children and implement actual behavior

Answer

Leaf nodes are the basic elements of a tree with no children; they perform actual work rather than delegating to sub-components.

Question 5

When should you prefer the Bridge pattern over simple inheritance?

Accepted Answer

When both abstraction and implementation need to be extensible independently

Answer

Bridge avoids the exponential growth of subclasses that occurs when both the abstraction and implementation have multiple dimensions of variation.

Pattern Design Practice Test

Pattern Design Practice Test

Pattern Design Structural Design Patterns 2