Summary

Question 1

Strategy

Answer 1

Encapsulates interchangeable behaviors and uses delegation to decide which one to use.

Question 2

Adapter

Answer 2

Changes the interface of one or more classes.

Question 3

Iterator

Answer 3

Provides a way to traverse a collection of objects without exposing the collection’s implementation.

Question 4

Facade

Answer 4

Simplifies the interface of a group of classes.

Question 5

Composite

Answer 5

Clients treat collection of objects and individual objects uniformly.

Question 6

Observer

Answer 6

Allows a group of objects to be notified when some state changes.

Question 7

Decorator

Answer 7

Wraps an object to provide new behavior.

Question 8

State

Answer 8

Encapsulates state-based behaviors and uses delegation to switch between behaviors.

Question 9

Proxy

Answer 9

Wraps an object to control access to it.

Question 10

Factory

Answer 10

Subclasses decide which concrete classes to create.

Question 11

Template Method

Answer 11

Subclasses decide how to implement steps in an algorithm.

Question 12

Singleton

Answer 12

Ensures one and only one object is created.

Question 13

Abstract Factory

Answer 13

Allows a client to create families of objects without specifying their concrete classes.

Question 14

Command

Answer 14

Encapsulates a request as an object.