菜鳥翻譯（YIChangKong）

Gang of Four Design Patterns(設(shè)計(jì)模式四門派)

OverView(概述)

Over 20 years ago the iconic computer science book “Design Patterns: Elements of Reusable Object-Oriented Software” was first published.

The four authors of the book: Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, have since been dubbed “The Gang of Four”. In technology circles, you’ll often see this nicknamed shorted to GoF. Even though the GoF Design Patterns book was published over 20 years ago, it still continues to be an Amazon best seller.

20多年前，標(biāo)志性的計(jì)算機(jī)科學(xué)著作“設(shè)計(jì)模式：可重用的面向?qū)ο筌浖脑亍笔状纬霭?。關(guān)于這個(gè)本書的四位作者: Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides,此后被成為“四人幫” ，在技術(shù)界，您經(jīng)常會(huì)看到這個(gè)昵稱，簡(jiǎn)稱GoF。即使GoF Design Patterns一書出版了20多年，它仍然繼續(xù)是亞馬遜的暢銷書。

The GoF wrote the book in a C++ context but it still remains very relevant to Java programming. C++ and Java are both object-oriented languages. The GoF authors, through their experience in coding large scale enterprise systems using C++, saw common patterns emerge. These design patterns are not unique to C++. The design patterns can be applied in any object oriented language.

GoF用c++編寫了這本書，但它仍然與Java編程非常相關(guān)。c++和Java都是面向?qū)ο蟮恼Z(yǔ)言。GoF的作者通過(guò)使用c++編寫大型企業(yè)系統(tǒng)的經(jīng)驗(yàn)，看到了常用模式的出現(xiàn)。這些設(shè)計(jì)模式并不是c++獨(dú)有的。設(shè)計(jì)模式可以應(yīng)用于任何面向?qū)ο笳Z(yǔ)言。（擴(kuò)展：C++ is a combination of both procedural and object-oriented programming languages.）

As a Java developer using the Spring Framework to develop enterprise class applications, you will encounter the GoF Design Patterns on a daily basis.

作為一名使用Spring框架開發(fā)企業(yè)級(jí)應(yīng)用程序的Java開發(fā)人員，您每天（daily basis）都會(huì)遇到GoF設(shè)計(jì)模式。

The GoF Design Patterns are broken into three categories: Creational Patterns for the creation of objects; Structural Patterns to provide relationship between objects; and finally, Behavioral Patterns to help define how objects interact.

GoF設(shè)計(jì)模式可分為三類:用于創(chuàng)建對(duì)象的創(chuàng)建模式;提供對(duì)象之間關(guān)系的結(jié)構(gòu)模式;最后，行為模式幫助定義對(duì)象如何交互。

Creational Design Patterns（創(chuàng)建型模式）

• Abstract Factory. Allows the creation of objects without specifying their concrete type.

• 抽象工廠模式：允許在不指定對(duì)象具體類型(對(duì)象類型)的情況下創(chuàng)建對(duì)象

• Builder. Uses to create complex objects.

• 建造者模式（Builder）：用于創(chuàng)建復(fù)雜對(duì)象。

• Factory Method. Creates objects without specifying the exact class to create.

• 工廠方法模式：創(chuàng)建對(duì)象，而不指定要?jiǎng)?chuàng)建的確切類。

• Prototype.（原型） Creates a new object from an existing object.

• 原型模式（Prototype）：從現(xiàn)有對(duì)象創(chuàng)建新對(duì)象。

• Singleton. Ensures only one instance of an object is created.

• 單例模式（Singleton）：確保只創(chuàng)建對(duì)象的一個(gè)實(shí)例。

Structural Design Patterns（結(jié)構(gòu)型模式）

• Adapter. Allows for two incompatible classes to work together by wrapping an interface around one of the existing classes.

• 適配器模式(Adapter)：允許兩個(gè)不兼容的類通過(guò)在一個(gè)現(xiàn)有類周圍包裝一個(gè)接口一起工作。

• Bridge. Decouples an abstraction so two classes can vary independently.

• 橋接模式(Bridge)：解耦一個(gè)抽象，這樣兩個(gè)類可以獨(dú)立變化。（抽象分離？？）

• Composite. Takes a group of objects into a single object.

• 組合模式(Composite)：將一組對(duì)象轉(zhuǎn)換為單個(gè)對(duì)象

• Decorator. Allows for an object’s behavior to be extended dynamically at run time.

• 裝飾模式(Decorator)**裝飾模式(Decorator)**：允許對(duì)象在運(yùn)行時(shí)動(dòng)態(tài)擴(kuò)展對(duì)象的行為。

• Facade. Provides a simple interface to a more complex underlying object.

• 外觀模式(Facade)：為更復(fù)雜的底層對(duì)象提供一個(gè)簡(jiǎn)單的接口。

• Flyweight. Reduces the cost of complex object models.

• （輕量化）享元模式(Flyweight)：降低復(fù)雜對(duì)象模型的成本（任務(wù)？）。

• Proxy. Provides a placeholder interface to an underlying object to control access, reduce cost, or reduce complexity.

• 代理模式(Proxy)：為基礎(chǔ)對(duì)象提供占位符接口，以控制訪問(wèn)、降低成本或降低復(fù)雜性。

Behavior Design Patterns（行為型模式）

• Chain of Responsibility. Delegates commands to a chain of processing objects.

• 職責(zé)鏈模式(Chain of Responsibility)： ?將命令委托給處理對(duì)象鏈。

• Command. Creates objects which encapsulate actions and parameters.

• 命令模式(Command)：創(chuàng)建一個(gè)封裝動(dòng)作和參數(shù)的對(duì)象

• Interpreter. Implements a specialized language.

• 解釋器模式(Interpreter)：實(shí)現(xiàn)一種特定的語(yǔ)言

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

• 迭代器模式(Iterator)：按順序訪問(wèn)對(duì)象的元素，而不公開其底層表示。（sequencetially 按順序）

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

• 中介者模式(Mediator)：通過(guò)成為唯一詳細(xì)了解其方法的類，實(shí)現(xiàn)允許類之間的松耦合。

• Memento. Provides the ability to restore an object to its previous state.

• 備忘錄模式(Memento)：提供將對(duì)象恢復(fù)到以前狀態(tài)的能力。

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

• 觀察者模式(Observer)：是一個(gè)發(fā)布/訂閱模式，它允許多個(gè)觀察者對(duì)象查看事件。

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

• 狀態(tài)模式(State)：允許對(duì)象在其內(nèi)部狀態(tài)改變時(shí)改變其行為。

• Strategy. Allows one of a family of algorithms to be selected on-the-fly at run-time.

• 策略模式(Strategy):允許一個(gè)算法族在運(yùn)行時(shí)被選中。

• Template Method. Defines the skeleton of an algorithm as an abstract class, allowing its sub-classes to provide concrete behavior.

• 模板方法模式(Template Method)：將算法的骨架定義為抽象類，從而允許其子類提供具體的行為

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

• 訪問(wèn)者模式(Visitor)：通過(guò)將方法的層次結(jié)構(gòu)移動(dòng)到一個(gè)對(duì)象中，將一種算法與一種對(duì)象結(jié)構(gòu)分離。