Design Patterns

Question 1

Abstract Factory

Answer 1

Groups object factories that have a common theme.

Question 2

Builder

Answer 2

Constructs complex objects by separating construction and representation.

Question 3

Factory Method

Answer 3

Creates objects without specifying the exact class to create.

Question 4

Prototype

Answer 4

Creates objects by cloning an existing object.

Question 5

Singleton

Answer 5

Restricts object creation for a class to only one instance.

Question 6

Adapter

Answer 6

Allows classes with incompatible interfaces to work together by wrapping its own interface around that of an already existing class.

Question 7

Bridge

Answer 7

Decouples an abstraction from its implementation so that the two can vary independently.

Question 8

Composite

Answer 8

Composes zero-or-more similar objects so that they can be manipulated as one object.

Question 9

Decorator

Answer 9

Dynamically adds/overrides behavior in an existing method of an object.

Question 10

Facade

Answer 10

Provides a simplified interface to a large body of code.

Question 11

Flyweight

Answer 11

Reduces the cost of creating and manipulating a large number of similar objects.

Question 12

Proxy

Answer 12

Provides a placeholder for another object to control access, reduce cost, and reduce complexity.

Question 13

Chain of Responsibility

Answer 13

Delegates commands to a chain of processing objects.

Question 14

Command

Answer 14

Creates objects which encapsulate actions and parameters.

Question 15

Interpreter

Answer 15

Implements a specialized language.

Question 16

Iterator.

Answer 16

Accesses the elements of an object sequentially without exposing its underlying representation.

Question 17

Mediator

Answer 17

Allows for loose coupling between classes by being the only class that has detailed knowledge of their methods.

Question 18

Memento

Answer 18

Provides the ability to restore an object to its previous state (undo).

Question 19

Observer

Answer 19

is a publish/subscribe pattern which allows a number of observer objects to see an event.

Question 20

State

Answer 20

Allows an object to alter its behavior when its internal state changes.

Question 21

Strategy

Answer 21

Allows one of a family of algorithms to be selected on-the-fly at runtime.

Question 22

Template Method

Answer 22

Defines the skeleton of an algorithm as an abstract class, allowing its subclasses to provide concrete behavior.

Question 23

Visitor

Answer 23

Separates an algorithm from an object structure by moving the hierarchy of methods into one object.

Question 24

Groups object factories that have a common theme.

Answer 24

Abstract Factory

Question 25

Constructs complex objects by separating construction and representation.

Answer 25

Builder

Question 26

Creates objects without specifying the exact class to create.

Answer 26

Factory Method

Question 27

Creates objects by cloning an existing object.

Answer 27

Prototype

Question 28

Restricts object creation for a class to only one instance.

Answer 28

Singleton

Question 29

Allows classes with incompatible interfaces to work together by wrapping its own interface around that of an already existing class.

Answer 29

Adapter

Question 30

Decouples an abstraction from its implementation so that the two can vary independently.

Answer 30

Bridge

Question 31

Composes zero-or-more similar objects so that they can be manipulated as one object.

Answer 31

Composite

Question 32

Dynamically adds/overrides behavior in an existing method of an object.

Answer 32

Decorator

Question 33

Provides a simplified interface to a large body of code.

Answer 33

Facade

Question 34

Reduces the cost of creating and manipulating a large number of similar objects.

Answer 34

Flyweight

Question 35

Provides a placeholder for another object to control access, reduce cost, and reduce complexity.

Answer 35

Proxy

Question 36

Delegates commands to a chain of processing objects.

Answer 36

Chain of Responsibility

Question 37

Creates objects which encapsulate actions and parameters.

Answer 37

Command

Question 38

Implements a specialized language.

Answer 38

Interpreter

Question 39

Accesses the elements of an object sequentially without exposing its underlying representation.

Answer 39

Iterator.

Question 40

Allows for loose coupling between classes by being the only class that has detailed knowledge of their methods.

Answer 40

Mediator

Question 41

Provides the ability to restore an object to its previous state (undo).

Answer 41

Memento

Question 42

is a publish/subscribe pattern which allows a number of observer objects to see an event.

Answer 42

Observer

Question 43

Allows an object to alter its behavior when its internal state changes.

Answer 43

State

Question 44

Allows one of a family of algorithms to be selected on-the-fly at runtime.

Answer 44

Strategy

Question 45

Defines the skeleton of an algorithm as an abstract class, allowing its subclasses to provide concrete behavior.

Answer 45

Template Method

Question 46

Separates an algorithm from an object structure by moving the hierarchy of methods into one object.

Answer 46

Visitor