Software Design Patterns

Front 1

Composite

Back 1

Compose objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly.

Front 2

Interpreter

Back 2

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

Front 3

Visitor

Back 3

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.

Front 4

Adapter or Wrapper

Back 4

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

Front 5

Template method

Back 5

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 algorithm's structure.

Front 6

Facade

Back 6

Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.

Front 7

Observer or Publish/subscribe

Back 7

Define a one-to-many dependency between objects where a state change in one object results with all its dependents being notified and updated automatically.

Front 8

Command

Back 8

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

Front 9

Strategy

Back 9

Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.