Object Oriented Design Patterns Flashcards
Understand the fundamentals of object oriented design patterns.
Abstract Factory
Provide an interface for creating families of related or dependent objects without specifying their concrete classes.
Purpose: Creational
Scope: Object
Adapter
Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn’t otherwise because of incompatible interfaces.
Purpose: Structural
Scope: Class and Object
Bridge
Decouple an abstraction from its implementation so that the two can vary independently.
Purpose: Structural
Scope: Object
Builder
Separate the construction of a complex object from its representation so that the same construction process can create different representations.
Decorator
Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.
Purpose: Structural
Scope: Object
Facade
Provide a unified interface to a set of interfaces in a subsystem. Facade defines: higher-level interface that makes the subsystem easier to use.
Purpose: Structural
Scope: Object
Factory Method
Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.
Purpose: Creational
Scope: Class
Flyweight
Use sharing to support large numbers of fine-grained objects efficiently.
Purpose: Structural
Scope: Object
Chain of Responsibility
Avoid 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.
Purpose: Behavioral
Scope: Object
Command
Encapsulate a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.
Purpose: Behavioral
Scope: Object
Composite
Compose objects, into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly.
Purpose: Structural
Scope: Object
Visitor
Represent an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates.
Purpose: Behavioral
Scope: Object
Template Method
Define the skeleton of an algorithm in an operation, deferring some steps ‘ to subclasses. Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithmʼs structure.
Purpose: Behavioral
Scope: Class
Strategy
Define a family of algorithms, encapsulate each one, and make them interchange- able. Strategy lets the algorithm vary independently from clients that use it.
Purpose: Behavioral
Scope: Object
State
Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.
Purpose: Behavioral
Scope: Object
Singleton
Ensure a class only has one instance, and provide a global point of access to it.
Purpose: Creational
Scope: Object
Proxy
Provide a surrogate or placeholder for another object to control access to it.
Purpose: Structural
Scope: Object
Prototype
Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype.
Purpose: Creational
Scope: Object
Interpreter
Given a language, define a represention for its grammar along with an interpreter that uses the representation to interpret sentences in the language.
Purpose: Behavioral
Scope: Class
Iterator
Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation.
Purpose: Behavioral
Scope: Object
Mediator
Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you
vary their interaction independently.
Purpose: Behavioral
Scope: Object
Memento
Without Violating encapsulation, capture and externalize an objectʼs internal state so that the object can be restored to this state later
Purpose: Behavioral
Scope: Object
Observer
Define a one-to-many dependency between objects so that when one object
changes state, all its dependents are notified and updated automatically.
Purpose: Behavioral
Scope: Object
