Gang Of Four Design Patterns Intent And Categorization

Front 1

Provides an interface for creating families of related or dependent objects without specifying their concrete classes.

Back 1

Abstract Factory

Front 2

Separates the construction of a complex object from its representation so that the same construction process can create different representations.

Back 2

Builder

Front 3

Defines an interface for creating an object, but lets subclasses decide which class to instantiate. Lets a class defer instantiation to subclasses.

Back 3

Factory Method

Front 4

Specifies the kinds of objects to create using an instance, and creates new objects by copying this instance.

Back 4

Prototype

Front 5

Ensures a class has only one instance, and provides a global point of access to it.

Back 5

Singleton

Front 6

Converts the interface of a class into another interface clients expect. Lets classes work together that couldn't otherwise because of incompatible interfaces.

Back 6

Adapter

Front 7

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

Back 7

Bridge

Front 8

Composes objects into tree structures to represent whole-part hierarchies. This pattern lets clients treat individual objects and object compositions uniformly.

Back 8

Composite

Front 9

Attaches additional responsibilities to an object dynamically. Provides a flexible alternative to subclassing for extending functionality.

Back 9

Decorator

Front 10

Provides a unified interface to a set of interfaces in a subsystem. Defines a higher-level interface that makes the subsystem easier to use.

Back 10

Facade

Front 11

Uses sharing to support large numbers of fine-grained objects efficiently.

Back 11

Flyweight

Front 12

Provides a surrogate or placeholder for another object to control access to it.

Back 12

Proxy

Front 13

Avoids coupling the sender of a request to its receiver by giving more than one object a chance to handle the request. Chain the receiving objects and pass the request along the chain until an object handles it.

Back 13

Chain of Responsibility

Front 14

Encapsulates a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.

Back 14

Command

Front 15

Given a language, define a representation for its grammar along with an ___________ that uses the representation to interpret sentences in the language.

Back 15

Interpreter

Front 16

Provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation.

Back 16

Iterator

Front 17

Define an object that encapsulates how a set of objects interact. Promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently.

Back 17

Mediator

Front 18

Without violating encapsulation, capture and externalize an object's internal state so that the object can be restored to this state later.

Back 18

Memento

Front 19

Defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

Back 19

Observer

Front 20

Allows an object to alter its behaviour when its internal _____ changes. The object will appear to change its class.

Back 20

State

Front 21

Defines a family of algorithms, encapsulates each one, and makes them interchangeable. Lets the algorithm vary independently from the clients that use it.

Back 21

Strategy

Front 22

Defines the skeleton of an algorithm in an operation, deferring some steps to subclasses. Lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure.

Back 22

Template Method

Front 23

Represents an operation to be performed on the elements of an object structure. Lets you define a new operation without changing the classes of the elements on which it operates.

Back 23

Visitor